too big for one's britches

alternative too big for one's breeches

1. idiomaticnot comparableDisturbingly confident; unacceptably cocky.

   A diffident, dedicated man, Bradley seemed the personification of rectitude. He never got too big for his britches.

   1989 May 22, Edwin M. Reingold, “Hard Times for Teflon Tom”, in TIME, archived from the original on 22 Oct 2010

   1 more example

   "There was a reward, I heard. That would pay the doctor and the hotel." "You ain't going to collect it,' Bert informed him. "It'd make you too big for your britches."

   1949, Dorothy M. Johnson, The Man Who Shot Liberty Valance; in Indian Country, London: Corgi, 1961, page 103

   Synonyms: too big for one's boots

2. not comparableUsed other than figuratively or idiomatically: Too large to fit into one's pants.