precautionn.[F. prcation, L. praecautio, fr. praecavere, praecautum, to guard against beforehand; prae before + cavere be on one's guard. See Pre-, and Caution.]1. Previous caution or care; caution previously employed to prevent mischief or secure good; as, his life was saved by precaution.()They [ancient philosophers] treasured up their supposed discoveries with miserable precaution. (J. H. Newman.)2. A measure taken beforehand to ward off evil or secure good or success; a precautionary act; as, to take precautions against accident.()v. t.[Cf. F. prcautionner.]1. To warn or caution beforehand.(Locke.)()2. To take precaution against.(Dryden.)