adjective

invaluable

invaluable, priceless, extremely useful

Her help was invaluable to the project.

Her help was invaluable to the project.

This book is an invaluable resource for students.

This book is an invaluable resource for students.

((...)) to (sb./sth.) extremely useful to (sb./sth.) Her help was invaluable to the project.

an invaluable ((noun)) an extremely useful (noun) This book is an invaluable resource.

Synonyms: priceless, precious; Antonyms: worthless, useless

From 'in-' (not) + 'valuable'. The prefix 'in-' here acts as an intensifier, meaning 'not able to be valued' or 'beyond value', not 'not valuable'.

Be careful! 'Invaluable' means extremely valuable, NOT 'not valuable'. It's a common mistake.

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