sicko UK /ˈsɪkəʊ/US /ˈsɪkoʊ/noun 3adjective 1forms 4 noun3 •A physically ill person.Sicko status: Can you keep going even when you're feeling out of sorts? — 2007 •(slang, offensive) A person with unpleasant tastes, views or habits.But in fact, the murders have been committed by an army of sickos, a phalanx of wild-eyed droolers led by a monster goon with a concrete jaw and a Neanderthal brow. — 1986 •(slang, offensive) A mentally ill person.You're a gambler, huh? A sicko like Essay? — 2011 adjective1 •Characterized by depraved tastes or habits; deviant.“I didn't want that pediatrician to touch me, he was, like, a very weird guy, very sicko.” He took pictures of her genitals, and she later wondered whether this was for child pornography. — 2012 formssickoes · sickos · more sicko · most sicko