Crack-up and Rear ender

Crack-up noun - A mental or nervous collapse.

Rear ender and crack-up are semantically related in unexpected topic. In some cases you can use "Rear ender" instead a noun phrase "Crack-up".

Crack-up and rear ender are semantically related in collision topic. Sometimes you can use "Crack-up" instead a noun phrase "Rear ender", if it concerns topics such as accident, wreck, unexpected.