make an ass of oneself/someone, to

make an ass of oneself/someone, to

To make an utter fool of oneself or someone else. This term has been current since Shakespeare’s time, for the “ass”—along with the donkey—has been equated with stupidity and foolishness since Cicero’s day. A ruder version is to make a horse’s ass (a horse’s behind) of someone.
See also: ass, make, of