Jizz or the act of jizzing (masturbation).

Means its all good or im ayt

A coded word that brings attention to the fact that someone in the vicinity is making a move on the opposite sex (without being obvious). The move being made may be overt, subtle, physical, flirting etc. Checks are usually done to embarrass the parties involved.
Advanced users may make a more complex coding system such as check-plus, check-minus, j-check, s-check etc which may be user defined.

In chess, to threaten capture of the opposing king.

To re-evaluate one's position, and or actions

The word used to express excitement during sports betting when you are in position for a payout. "Check!" Originated as a successful leg on a sports betting parlay.

Someone that has no definition between their chin and neck. It goes from nose, mouth, to chin-neck, shoulders, knees and toes.