lax /læks/adjective 6noun 3forms 3phrases 1 adjective6 •Lenient and allowing for deviation; not strict.The rules are fairly lax, but you have to know which ones you can bend. •Lacking care; neglectful, negligent. •Loose; not tight or taut.The rope fell lax. •(of a vowel) Produced with relatively little constriction of the vocal tract. •Describing an associative monoidal functor. •(no longer used) Having a looseness of the bowels; diarrheic. noun3 •(slang) lacrosse.“I'm not playing lax this term,” Mimah said. — 2010 •(informal) Clipping of laxative. •(dialect, UK) A salmon. formslaxes · laxer · laxest Phrases with lax lax upTo relax; to become lax; to ease up.