UNSTABLE

adjective Date: 13th century not stable ; not firm or fixed ; not constant: as, not steady in action or movement ; irregular , wavering in purpose or intent ; vacillating, lacking steadiness ; apt to move, sway, or fall , d. liable to change or alteration , readily changing (as by decomposing) in chemical or physical composition or in biological activity, characterized by lack of emotional control, see: inconstant ~ness noun unstably adverb