(v. t.) To conceive, or form an opinion of, beforehand; to form a previous notion or idea of.

ad-lib anticipate be caught napping be predisposed be surprised be taken unawares be unprepared blow it butt in dive into extemporize foreglimpse forejudge forerun foresee forestall foretaste get ahead of go before have no plan improvise interrupt intrude judge beforehand jump the gun play by ear plunge plunge headlong plunge into preconceive preconclude predecide predetermine prejudge presume presuppose presurmise rush into speak inopportunely speak too late win the start