Does 'inflammable' mean the same as 'flammable'?

Yes, they are synonyms. Both mean 'easily set on fire'.

Why does 'inflammable' look like it should mean 'not flammable'?

The 'in-' prefix here comes from the Latin verb 'inflammare' (to set on fire), not the English negative prefix. It's a historic source of confusion.

Which word should I use, 'flammable' or 'inflammable'?

For maximum clarity, especially in safety contexts, use 'flammable'. 'Inflammable' is correct but can be misunderstood and is now less common.

Can 'inflammable' be used about people or emotions?

Yes, metaphorically. For example, 'an inflammable temper' means a temper that is easily aroused or angered.

inflammable

UK/ɪnˈflæm.ə.bəl/US/ɪnˈflæm.ə.bəl/

Technical (Safety), Formal written (metaphorical use)

My Flashcards

Definition

Meaning

Easily set on fire; capable of burning.

Also used metaphorically to describe situations or temperaments that are easily excited or provoked.

Linguistics

Semantic Notes

Despite the prefix 'in-', this word is not a negation; it is a synonym of 'flammable'. Historically, 'inflammable' is the older term from Latin, but due to widespread misinterpretation, 'flammable' is now preferred on safety labels.

Dialectal Variation

British vs American Usage

Differences

Both forms are understood. The UK tends to retain 'inflammable' slightly more in formal and technical contexts, while the US has moved more decisively towards 'flammable' for safety clarity.

Connotations

In both, 'inflammable' can sound more formal or literary than 'flammable', especially in metaphorical use.

Frequency

'Flammable' is more frequent in modern technical and safety signage in both regions. 'Inflammable' is less common in everyday speech.

Vocabulary

Collocations

strong

highly inflammableinflammable materialinflammable liquidinflammable gas

medium

inflammable substancepotentially inflammabledangerously inflammable

weak

inflammable mixtureinflammable natureremain inflammable

Grammar

Valency Patterns

be + inflammablebe considered inflammabledeem + object + inflammable

Vocabulary

Synonyms

Strong

ignitablefiery

Neutral

flammablecombustible

Weak

burnableincendiary

Vocabulary

Antonyms

non-flammablenon-combustiblefireproofincombustibleflame-retardant

Phrases

Idioms & Phrases

“[No major idioms for 'inflammable' itself. The metaphorical use is treated as figurative language.]”

Usage

Context Usage

Business

Used in safety documentation, logistics, and material specifications (e.g., 'The shipment contains inflammable goods.').

Academic

Found in chemistry, engineering, and materials science texts.

Everyday

Rare; likely to be replaced by 'flammable' unless the speaker is using it metaphorically (e.g., 'He has an inflammable temper.').

Technical

The primary domain for its literal use, especially in older manuals, warning labels, and safety data sheets.

Examples

By Part of Speech

verb

British English

[No standard verb form. The related verb is 'inflame'.]

American English

[No standard verb form. The related verb is 'inflame'.]

adverb

British English

[No standard adverb form. 'Inflammably' is extremely rare.]

American English

[No standard adverb form. 'Inflammably' is extremely rare.]

adjective

British English

The old theatre curtains were made of highly inflammable fabric.
The debate on the topic remains inflammable.

American English

Check the label to see if the chemical is inflammable.
The political climate in the region is dangerously inflammable.

Examples

By CEFR Level

Be careful! That liquid is inflammable.

The factory stores inflammable materials in a special shed.
Gasoline is highly inflammable.

Due to its inflammable nature, the substance must be kept away from heat sources.
His inflammable temper often got him into trouble.

The report highlighted the dangerously inflammable mix of social inequality and political rhetoric.
Archivists must handle early film reels with care, as they are nitrate-based and highly inflammable.

Learning

Memory Aids

Mnemonic

Think of 'inflame' + 'able'. If something is able to be inflamed, it is 'inflammable'.

Conceptual Metaphor

ANGER/EXCITEMENT IS FIRE (e.g., an inflammable situation, an inflammable personality).

Watch out

Common Pitfalls

Translation Traps (for Russian speakers)

The Russian word 'нефламмабельный' is a false friend. The English 'inflammable' means ГОРЮЧИЙ/ВОСПЛАМЕНЯЮЩИЙСЯ, not its opposite. The English opposite is 'non-flammable'.

Common Mistakes

Using 'inflammable' to mean 'not flammable'. Adding 'in-' as a negative prefix is the most common and dangerous error.
Overusing 'inflammable' in casual speech where 'flammable' is more typical.

Practice

Quiz

Fill in the gap

For safety, all materials must be clearly labelled with a warning symbol.

Multiple Choice

What is the key relationship between 'inflammable' and 'flammable'?

FAQ

Frequently Asked Questions

: Yes, they are synonyms. Both mean 'easily set on fire'.
: The 'in-' prefix here comes from the Latin verb 'inflammare' (to set on fire), not the English negative prefix. It's a historic source of confusion.
: For maximum clarity, especially in safety contexts, use 'flammable'. 'Inflammable' is correct but can be misunderstood and is now less common.
: Yes, metaphorically. For example, 'an inflammable temper' means a temper that is easily aroused or angered.