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

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 out of

see under make a fool of.
See also: make, monkey, of, out
The American Heritage® Dictionary of Idioms by Christine Ammer.

make a monkey out of someone

or

make a monkey of someone

OLD-FASHIONED
If someone makes a monkey out of you, or makes a monkey of you, they do something that makes you seem ridiculous or stupid. The teenage footballer made monkeys out of men twice his age with his spectacular goals. If you follow the proper steps, you won't make a monkey of yourself.
See also: make, monkey, of, out, someone
Collins COBUILD Idioms Dictionary, 3rd ed.

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

make a ˈmonkey out of somebody

make somebody seem stupid or foolish: No one makes a monkey out of me.
See also: make, monkey, of, out, somebody
Farlex Partner Idioms Dictionary
See also:
  • make a monkey of someone
  • 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