cuss out verb1 •(US, informal) To berate (someone or something) using profane language; to swear at (someone or something), especially at length.[A]fter winning a berth on the U.S. Davis Cup team, he was dropped from the competition for the ungentlemanly way in which he cussed out a ball boy. — 1969 formscussed out · cussing out · cusses out