A contraction of "Let's See". Can be used as either street slang, or internet slang. Also spelt "Lessee".
Uber-1337 version would be 13553, although this is not commonly used.

Use this expression with some news you´re sure that will surprise the other person.

A word used to describe the word Let's but in an extremely thug-like way.

You are all wrong.
Less means "bet" or "ok"

The opposite of being extra

another word for “say less” or “say no more”, meaning you fully understood and/or in agreement with what’s being said

phony or false