What exactly is a "nit"?

[Wiggin]

I tried using the search function and checked the links to different poker definitions, but can't seem to find a definition for it.

[phydaux]

Someone who plays very tight. A rock.

"That player is tight as a nit."

[Daddy Warbucks]

Also generally somebody who doesn't like to gamble.

[KurtSF]

Someone who likes to nit pick.

[Frond]

Would you classify someone a nit who raises KK preflop, check calls all the way, makes a set of Kings on the river and opts to check and call them, and then wins?

[KurtSF]

Depends.

[DannyNSandy]

rock