make a monkey of someone

make a monkey (out) of (someone or oneself)

To do something that makes someone (or oneself) seem stupid or ridiculous. I know Greg is only trying to impress Lisa, but he's making a monkey out of himself by telling so many corny jokes. I'm not going to dance too much at the party because I don't want to make a monkey out of myself in front of my coworkers.
See also: make, monkey, of
Farlex Dictionary of Idioms.

make a monkey of (or out of) someone

humiliate someone by making them appear ridiculous.
See also: make, monkey, of, someone
Farlex Partner Idioms Dictionary
See also:
  • make a monkey (out) of (someone or oneself)
  • make a monkey out of
  • impress (something) into (something)
  • impress into
  • knock (one) cold
  • knock cold
  • a somebody
  • knock the socks off
  • knock the socks off (someone or something)
  • knock the socks off someone