He is acting too big for his britches lately.
too big for one's britches
idiomDisturbingly confident, unacceptably cocky.
Origin
disputed originUS origin, 19th c.
After his promotion, he started acting too big for his britches and ignored his old friends.
The young executive became far too big for his britches, eventually alienating the very mentors who had helped him climb the corporate ladder.
- 01
abound in one's own sense
To follow one’s own inclinations and opinions.
- 02
ace up one's sleeve
A surprise advantage of which others are not aware.
- 03
act one's age
To behave in a manner appropriate to one's age.
- 04
act one's age, not one's shoe size
Synonym of act one's age (“to behave in a mature manner; to avoid being childish”).
- 05
afraid of one's own shadow
Exceptionally timid.
- 06
air one's dirty laundry in public
To reveal one's sordid secrets to the public.
- 07
air one's dirty linen in public
Synonym of air one's dirty laundry in public.
- 08
albatross around one's neck
A characteristic, possession, associate, or previous deed that hinders one's ability to succeed.
Last updated July 12, 2026