1. rude slang To be or become wildly or uncontrollably angry. My parents went totally apeshit when they found out I'd wrecked the car!Now, don't go apeshit or anything, but I've decided to move to Canada.
2. rude slang To be or become extremely excited or enthusiastic (about something). I've never understood that pop star's popularity, but kids just go apeshit over her music.