let's go

Short definition from Wiktionary

Phrase

1. 1
   Hortative of go, particularly as a cheer expressing encouragement.
2. 2
   Let us begin or get started. (a call to put a plan into action)
3. 3
   Hurry up; be quick.
4. 4
   Bring it on. (an incitement to fight)
5. 5
   Yay. (an expression of pleasure, joy, relief, or satisfaction)