late 14c., "tread or step lightly and nimbly, skip, dance, caper," from Old French triper "jump around, dance around, strike with the feet" (12c.), from a Germanic source (compare Middle Dutch trippen "to skip, trip, hop; to stamp, trample," Low German trippeln, Frisian tripje, Dutch trappen, Old English treppan "to tread, trample") related to trap (n.).
The senses of "to stumble" (intransitive), "strike with the foot and cause to stumble" (transitive) are from mid-15c. in English. Meaning "to release" (a catch, lever, etc.) is recorded from 1897; trip-wire is attested from 1868. Related: Tripped; tripping.
"act or action of tripping" (transitive), early 14c., from trip (v.); sense of "a short journey or voyage" is from mid-15c.; the exact connection to the earlier sense is uncertain. The meaning "psychedelic drug experience" is first recorded 1959 as a noun; the verb in this sense is from 1966, from the noun.