1 a [no obj] : to hit your foot against something while you are walking or running so that you fall or almost fall
▪ Be careful. Don't trip. — often + on or over ▪ He tripped [=stumbled] over the curb. ▪ She tripped on the stairs and almost fell.
b [+ obj] : to cause (someone who is walking or running) to fall or almost fall
▪ He deliberately tried to trip me. — often + up ▪ He got tripped up by the wires on the floor. 2 always followed by an adverb or preposition [no obj] literary : to dance or walk with light, quick steps
▪ The dancers tripped off the stage. 3 [+ obj] : to cause (something, such as an alarm or a switch) to be turned on often in an accidental way
▪ Burglars smashed in the window and tripped [=set off] the alarm. ▪ She tripped [=threw] the switch. 4 [no obj] informal : to experience strange mental effects (such as seeing things that are not real) after taking a very powerful drug (such as LSD) — often + on ▪ They were tripping on acid.