get too big for (one's) britches

get too big for (one's) britches

To become overconfident in one's importance, skill, or authority; to start speaking or behaving as if one is more important or influential than one actually is. He's gotten too big for his britches ever since he got that promotion. Honestly, John got too big for his britches as soon as pro teams started scouting him.
See also: big, britches, get
Farlex Dictionary of Idioms.
See also:
  • britches
  • a prophet is not without honor save in his own country
  • (one) could use (something)
  • as one door closes, another (one) opens
  • as one door closes, another one opens
  • as one door closes, another opens
  • drive (one) out of office
  • force (one) out of office
  • force out of office
  • give (one) (one's) head