high side noun 1high-side verb 1forms 4 noun1 •a type of motorcycle crash where the motorcycle tire loses, then rapidly regains traction, thus throwing the rider violently up, over, and off the motorcycle as the motorcycle spins off on its own trajectory. high-side verb1 •(slang) To show off; to strut.What do you expect, high-siding in those rags? Man, you are a walking neon sign advertising your vocation. — 1972 formshigh-sided · high-siding · high-sides · high sides