Lairize means: An obsolete Australian slang verb meaning to act in a flashy, ostentatious, or showy manner. Derived from 'lair' , this verb form is now largely dated. The noun 'lair' and adjective 'lairy' (gaudy,. The word is mostly archaic or historical; you will only encounter it in old texts, period drama, or school history rather than current teen conversation. It carries sexual or vulgar connotations; not alarming on its own but worth understanding the context your teen heard it in.