big head, have a

Idioms

Be conceited; have an exaggerated sense of one's own importance or ability. For example, The constant flattery of his subordinates is bound to give Thomas a big head. [c. 1800] Also see swelled head.

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023