eat shit

Short definition from Wiktionary

Verb

1. 1
   To fall and land on one's face.
2. 2
   To experience a catastrophic breakdown.
3. 3
   To do something disgusting or strongly undesirable.
4. 4
   To be soundly defeated.
5. 5
   Used other than figuratively or idiomatically: see eat, shit.
6. 6
   To do nothing of importance; to idle.

Interjection

1. 1
   An expression of discontent or aggravation to another party.