Play video content EXCLUSIVE TMZ.com

John Caparulo did something a lot of comedians are doing -- busted on President Trump -- but this time a woman in the front row quickly and violently retaliated on Trump's behalf.

John -- who was a regular on Chelsea Handler's show -- was performing stand-up at The Comedy & Magic Club in Hermosa Beach, CA. He made a phallic joke about the Washington Monument, and when he dragged the prez into it ... 2 women in the crowd went off.

One of them hurled f-bombs, the other upped the ante by launching her glass at him. You can tell, John was shocked and slightly injured -- he came really close to retaliating.