also destabilise, "deprive of stability," 1928 in a chemistry and physics sense; earlier (1919) with reference to political systems, commercial markets, etc.; see de- + stabilize. Related: Destabilized; destabilizing.
active word-forming element in English and in many verbs inherited from French and Latin, from Latin de "down, down from, from, off; concerning" (see de), also used as a prefix in Latin, usually meaning "down, off, away, from among, down from," but also "down to the bottom, totally" hence "completely" (intensive or completive), which is its sense in many English words.
As a Latin prefix it also had the function of undoing or reversing a verb's action, and hence it came to be used as a pure privative — "not, do the opposite of, undo" — which is its primary function as a living prefix in English, as in defrost (1895), defuse (1943), de-escalate (1964), etc. In some cases, a reduced form of dis-.
1861, originally of ships; probably a back-formation from stability, or else from French stabiliser. Related: Stabilized; stabilizing. Earlier verbs in the same sense were stabilitate (1640s) and simple stable (v.) "make steady or firm, make stable" (c. 1300), from Old French establir.