labile [LME] When labile first came into English via French from Latin labilis it had the very serious meaning ‘liable to sin’, as well as meaning ‘unreliable’. The Latin had a wide range of meanings including ‘smooth-flowing, unstable, uncertain’, leading to many different meanings for the word in the past. Nowadays it is most often used to mean changeable [E17th] and particularly of emotions that are easily aroused and which change quickly [L19th].