impingement

a forceful coming together of two things the impingement of the hailstones on the metal roof was making quite a racket Synonyms bump, collision, concussion, crash, impact, jar, jolt, jounce, kick, shock, slam, smash, strike, wallopRelated Words blow, buffet, hit, knock, punch, rap, slap, thump; bashing, battering, bludgeoning, clobbering, hammering, lambasting, licking, pounding, pummeling (also pummelling), thrashing; contact, encounter, meeting, touch