Formal vs Informal Vocabulary: 100+ Words and Examples

by | Aug 24, 2026 | English Vocabulary | 0 comments

Formal and informal vocabulary are used in different situations in English. Formal words are more common in professional, academic, and official communication, while informal words are commonly used in everyday conversations with friends, family, and people we know well.

Understanding the difference between formal and informal vocabulary can help you choose the right words for emails, conversations, essays, meetings, and other situations.

What Is Formal Vocabulary?

Formal vocabulary consists of words and expressions commonly used in professional, academic, business, and official situations.

For example:

  • purchase instead of buy

  • assist instead of help

  • inform instead of tell

  • require instead of need

Formal vocabulary generally sounds more professional and less conversational.

What Is Informal Vocabulary?

Informal vocabulary consists of words and expressions commonly used in everyday conversations and casual communication.

For example:

  • buy instead of purchase

  • help instead of assist

  • tell instead of inform

  • need instead of require

Informal English is especially common when speaking with friends, relatives, classmates, and people you know well.

Formal vs Informal Vocabulary

Informal Formal Example
ask inquire I would like to inquire about the position.
buy purchase You can purchase tickets online.
help assist Could you assist me with this issue?
tell inform Please inform us of any changes.
need require This position requires experience.
get obtain You must obtain permission first.
give provide Please provide additional information.
show demonstrate The results demonstrate significant improvement.
check verify Please verify your email address.
find out discover Researchers discovered a new method.

100+ Formal and Informal Words

[Add the complete vocabulary table here, organized into useful groups.]

Formal vs Informal Verbs

Include common pairs such as:

  • ask → inquire

  • buy → purchase

  • get → obtain

  • help → assist

  • tell → inform

  • show → demonstrate

  • fix → repair

  • put off → postpone

  • find out → discover

  • look into → investigate

Formal vs Informal Adjectives

Compare everyday adjectives with more formal alternatives.

Examples:

  • good → beneficial

  • bad → unfavorable

  • enough → sufficient

  • wrong → incorrect

  • cheap → inexpensive

Formal vs Informal Phrases

Compare complete expressions rather than individual words.

For example:

Informal: Thanks for your help.
Formal: Thank you for your assistance.

Informal: Sorry I’m late.
Formal: I apologize for the delay.

Informal: Can you send me the report?
Formal: Could you please send me the report?

Formal vs Informal Vocabulary in Emails

Explain how vocabulary changes between casual and professional emails.

Informal More Formal
Hi Dear Mr./Ms.
Thanks Thank you
Sorry I apologize
Can you…? Could you please…?
I need… I would require…
Let me know Please inform me
See you soon I look forward to seeing you

Formal vs Informal Vocabulary in Writing

Formal vocabulary is generally preferred in:

  • academic essays

  • reports

  • research papers

  • business documents

  • official letters

  • professional emails

Informal vocabulary is more appropriate for:

  • personal messages

  • social media

  • casual emails

  • conversations

  • texts to friends and family

Formal vs Informal Vocabulary in Speaking

The vocabulary you choose also depends on who you are speaking to.

You might say:

To a friend: “Can you help me with this?”

But in a professional situation:

To a colleague or client: “Could you assist me with this?”

Both sentences are correct. The difference is the level of formality.

When Should You Use Formal English?

Use formal English when communicating in professional, academic, official, or unfamiliar situations.

Common examples include job applications, business emails, academic writing, presentations, reports, and communication with customers or senior colleagues.

When Should You Use Informal English?

Informal English is appropriate for relaxed communication with friends, family members, classmates, and people you know well.

It is also widely used in text messages, casual conversations, personal emails, and social media.

Formal vs Informal Vocabulary: Quick Comparison

Formal English Informal English
professional conversational
more structured more relaxed
fewer contractions contractions are common
precise vocabulary everyday vocabulary
fewer slang expressions slang may be used
common in academic writing common in conversation

Frequently Asked Questions

What is formal vocabulary?

Formal vocabulary includes words and expressions typically used in professional, academic, business, and official communication.

What is informal vocabulary?

Informal vocabulary includes everyday words and expressions commonly used in casual conversations and personal communication.

What is an example of formal and informal vocabulary?

An example is assist and help. “Assist” is more formal, while “help” is neutral and commonly used in everyday English.

Is informal English grammatically incorrect?

No. Informal English is not necessarily incorrect. It simply suits different contexts from formal English.

Should I use formal vocabulary in academic writing?

Generally, yes. Academic writing usually requires clear, precise, and relatively formal language, although unnecessarily complicated vocabulary should be avoided.

Final Thoughts

Learning formal vs informal vocabulary helps you adjust your English to different situations. You do not always need to choose the most formal word. The important skill is knowing which level of formality is appropriate for your audience and purpose.

By learning common formal and informal word pairs and practicing them in context, you can communicate more naturally and effectively in both professional and everyday English.

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