mucousy adjective2 •(informal) Suggesting mucus; mucus-like; slimy. •(informal) Synonym of mucous.Do all the puppies seem healthy, with no mucousy discharge from the nose, no loose stools, and no foul smell from their ears? Are their coats clean and full? Do they have plenty of energy when awake? — 2005 formsmore mucousy · most mucousy