Know how to use "fewer" and "less"? Find out.
late 14c., "capable of perceiving, fitted for mental impression," from Medieval Latin apprehensivus, from Latin apprehensus, past participle of apprehendere (see apprehend). Meaning "fearful of what is to come" is recorded from 1718, via notion of "capable of grasping with the mind" (c.1600). Related: Apprehensively; apprehensiveness.