crack–up

1 a mental or nervous collapse a crack-up required him to take a year off from work Synonyms crack-up, nervous breakdown, tailspinRelated Words frazzle, freak-out, meltdown; alarm (also alarum), anxiety, apprehension, disquiet; excitability, nervousness; disturbance; agitation, discomposure, perturbation; basket caseNear Antonyms aplomb, calmness, composure, coolness, imperturbability, placidity, self-possession, sereneness, serenity, tranquillity (or tranquility), tranquilness

2 the violent coming together of two bodies into destructive contact two people were injured in a serious crack-up on the interstate Synonyms collision, concussion, crack-up, smash, smashup, wreckRelated Words accident, pileup; demolishment, destruction, ruin