Idioms are colorful expressions whose meanings go beyond the literal words. Instead of saying something directly, idioms paint a picture,
making communication more lively and emotional. For example, saying “we’re inseparable” is simple—but an idiom can make it more vivid and memorable.
When it comes to friendship, especially best friends, idioms help capture feelings that are often hard to express—loyalty, trust,
shared history, and even playful teasing. Whether you’re chatting casually, writing a message, or preparing for exams, using the right idioms for best friends can instantly make your English sound more natural and fluent.
In this guide, you’ll explore meaningful and expressive friendship idioms, along with practical examples and usage tips.
You’ll also discover how these phrases can improve your spoken English, enhance emotional expression, and boost your vocabulary skills in real-life conversations.
Quick Overview Table
| Idiom | Short Meaning | Tone | Common Use Context |
|---|---|---|---|
| Thick as thieves | Extremely close | Informal | Close friendships |
| Through thick and thin | Loyal in all situations | Neutral | Emotional support |
| Two peas in a pod | Very similar | Informal | Personality similarity |
| Partner in crime | Fun companion | Informal | Mischief/fun |
| Have someone’s back | Support/protect | Neutral | Trust situations |
| Ride or die | Ultimate loyalty | Informal | Strong bonds |
| Go way back | Long friendship | Neutral | History |
| Like a brother/sister | Deep emotional bond | Neutral | Family-like friendship |
| In someone’s corner | Always supporting | Slightly formal | Encouragement |
| Know someone inside out | Understand deeply | Neutral | Close understanding |
| Hit it off | Instantly connect | Informal | First meetings |
Detailed Idioms Section
Thick as thieves
Meaning: Two people who share a very tight bond and trust each other completely.
When to Use It: When describing best friends who are always together and share secrets.
Example Sentence: Ever since school, we’ve been thick as thieves.
Similar Expressions: Joined at the hip, inseparable
Opposite Expression: Drift apart
Through thick and thin
Meaning: Staying loyal regardless of good or bad situations.
When to Use It: To highlight emotional support during difficult times.
Example Sentence: She stood by me through thick and thin.
Similar Expressions: Always there, unwavering support
Opposite Expression: Abandon ship
Two peas in a pod
Meaning: Two people who are almost identical in personality or habits.
When to Use It: When friends think alike or behave similarly.
Example Sentence: They laugh at the same jokes—they’re like two peas in a pod.
Similar Expressions: Cut from the same cloth, birds of a feather
Opposite Expression: Worlds apart
Partner in crime
Meaning: A close friend who shares fun, adventures, or even harmless mischief.
When to Use It: For playful friendships full of shared experiences.
Example Sentence: She’s my partner in crime on every trip.
Similar Expressions: Sidekick, buddy
Opposite Expression: Lone wolf
Have someone’s back
Meaning: To support and defend someone no matter what.
When to Use It: In situations requiring trust and loyalty.
Example Sentence: Don’t worry—I’ve got your back.
Similar Expressions: Stand by someone, support
Opposite Expression: Betray someone
Ride or die
Meaning: A person who stays loyal no matter the risk or consequence.
When to Use It: For extremely strong, unbreakable friendships.
Example Sentence: He’s my ride or die—we’ve been through everything together.
Similar Expressions: Loyal to the core, true friend
Opposite Expression: Fair-weather friend
Go way back
Meaning: Knowing someone for a very long time.
When to Use It: To highlight shared history.
Example Sentence: We go way back to childhood days.
Similar Expressions: Long-time friend, childhood friend
Opposite Expression: Just met
Like a brother/sister
Meaning: A friend who feels like family.
When to Use It: For deep emotional connections beyond friendship.
Example Sentence: She’s not just my friend—she’s like a sister to me.
Similar Expressions: Family-like bond, close as kin
Opposite Expression: Stranger
In someone’s corner
Meaning: Supporting someone, especially during challenges.
When to Use It: When offering encouragement or emotional strength.
Example Sentence: No matter what happens, I’ll always be in your corner.
Similar Expressions: Backing someone, cheering on
Opposite Expression: Against someone
Know someone inside out
Meaning: To understand someone completely, including their habits and emotions.
When to Use It: For deep understanding in long-term friendships.
Example Sentence: I know her inside out—she can’t hide anything from me.
Similar Expressions: Know by heart, understand deeply
Opposite Expression: Misunderstand
Hit it off
Meaning: To quickly form a strong connection when meeting someone.
When to Use It: For instant friendships.
Example Sentence: We hit it off the moment we met.
Similar Expressions: Click instantly, connect quickly
Opposite Expression: Feel awkward
Categorize the Idioms
Idioms for Positive Situations
- Thick as thieves
- Two peas in a pod
- Hit it off
- Like a brother/sister
Idioms for Difficult Situations
- Through thick and thin
- Have someone’s back
- In someone’s corner
- Ride or die
Funny / Informal Idioms
- Partner in crime
- Ride or die
- Two peas in a pod
Formal / Professional Idioms
- In someone’s corner
- Have someone’s back
- Know someone inside out
How to Use These Idioms in Real Conversations
Workplace Example:
“I trust Sarah completely—she always has my back during presentations.”
Casual Conversation:
“We’ve been partners in crime since college!”
Writing Example (Email):
“I appreciate having you in my corner during this project—it means a lot.”
IELTS/Exam Tip:
Use idioms naturally in speaking tests, but avoid overuse. One or two well-placed idioms can significantly boost your fluency score.
Common Mistakes to Avoid
Literal misunderstanding:
Idioms are not meant to be taken word-for-word. “Partner in crime” doesn’t mean actual crime.
Wrong tone usage:
Avoid informal idioms like “ride or die” in professional writing.
Formal vs informal misuse:
Use neutral idioms in essays and formal speech, not slang-heavy ones.
Practice Exercise
Fill in the blanks
- We’ve been ______ since school days.
- She always has my ______ in tough times.
- They are like two ______ in a pod.
- He’s my ______ or die friend.
- We really ______ it off at the party.
- She stood by me through ______ and thin.
- He knows me inside ______.
- They are ______ as thieves.
- She’s always in my ______.
- He’s my partner in ______.
Multiple Choice
- “Have someone’s back” means:
a) Ignore someone
b) Support someone
c) Compete with someone - “Two peas in a pod” refers to:
a) Enemies
b) Similar people
c) Strangers - “Ride or die” shows:
a) Weak bond
b) Loyalty
c) Distance - “Hit it off” means:
a) Fight
b) Connect quickly
c) Avoid - “Go way back” means:
a) Recently met
b) Long history
c) Unknown
Writing Prompts
- Describe your best friend using at least 2 idioms.
- Write a short paragraph about a loyal friendship.
- Explain a situation where a friend supported you.
Answers
Fill in the blanks:
- go way back
- back
- peas
- ride
- hit
- thick
- out
- thick
- corner
- crime
MCQs:
1-b, 2-b, 3-b, 4-b, 5-b
FAQs
What are idioms for best friends?
They are expressions used to describe strong, close, and meaningful friendships.
Can I use these idioms in formal writing?
Some are suitable, but avoid very informal ones like “ride or die.”
How can I remember idioms easily?
Use them in daily conversation and practice with examples.
Are idioms important for IELTS?
Yes, they improve fluency and natural expression.
How many idioms should I learn daily?
Focus on 2–3 and practice them actively.
Conclusion
Learning idioms related to best friends is a powerful way to make your English more expressive and natural.
These phrases help you communicate emotions, loyalty, and shared experiences in a way that plain language often cannot capture.
Instead of memorizing long lists, focus on understanding how and when to use each idiom in real-life situations.
Practice them in conversations, writing, and even while thinking in English. Over time, they will become a natural part of your speech.
Mastering topic-based idioms like these not only improves your fluency but also boosts confidence, making your communication more engaging and authentic.
Corvin Hale is a language enthusiast who makes learning English idioms simple and fun.
