Suffix -OUS

Suffix -OUS

Learning how words are built helps you understand English better, especially for Cambridge exams like B2 First and C1 Advanced. When you notice how words are formed, you can learn new vocabulary faster and feel more confident using it. Suffix -OUS

What is a suffix?

A suffix is a letter or a group of letters added to the end of a word to change its meaning or grammatical form.

noun → adjective

verb → noun

adjective → adverb

Today, we will focus on one of the most useful suffixes for making adjectives:

The suffix -OUS

The suffix -OUS means:

• “full of”
• “having the quality of”
• “characterised by”

We usually add this suffix to nouns to make adjectives.

danger → dangerous

mystery → mysterious

You will see these adjectives often in formal writing, such as essays, reports, reviews, and descriptions.

Common adjectives ending in -OUS

Envious

Meaning: wanting something that belongs to another person.

• You shouldn’t be envious of people who have more than you do.

Dangerous

Meaning: able to cause harm or injury.

• Smoking is a dangerous habit.
• It can be dangerous to ignore safety rules.

Famous

Meaning: known by many people.

• Jennifer Lopez is a world-famous performer.
• The town is famous for its medieval castle.

Ambitious

Meaning: having a strong desire for success or achievement.

• John was extremely ambitious when he was young.
• Ambitious students often set clear long-term goals.

Miraculous

Meaning: extremely surprising or unexpected, often in a positive way.

• Houdini made a miraculous escape from the ropes.
• Doctors described her recovery as miraculous.

Nervous

Meaning: worried, anxious, or slightly afraid.

• I always feel nervous before an exam.
• She sounded nervous during the interview.

Mysterious

Meaning: difficult to explain or understand.

• The woman disappeared under mysterious circumstances.
• There was a mysterious noise coming from the attic.

Jealous

Meaning: unhappy because someone has something you want (or because of fear of losing someone).

• Rhina is jealous of her ex-husband’s new wife.
• He felt jealous when she started working with someone new.

Poisonous

Meaning: containing poison; able to cause illness or death.

• We saw a poisonous snake this morning.
• Some mushrooms are highly poisonous.

Spelling notes

Be careful: some nouns change a bit before you add -OUS:

mystery → mysterious (y → i)

envy → envious (y → i)

danger → dangerous (keep the e)

ambition → ambitious (-tion → -tious)

Common mistake:

❌ envyous

✅ envious

If you learn how to use suffixes well, you can choose the right word for any situation. This is what examiners want to see.

Exam tip

When you write or speak, using adjectives with -OUS can help you:

• sound more precise
• avoid repetition
• raise your Lexical Resource score

Compare:

It was very bad weather. ❌

It was extremely dangerous weather. ✅

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