1. 牙垢;牙石
Tartar is a hard yellowish substance that forms on your teeth and causes them to decay if it is not removed.
2. 凶悍的人,脾气暴戾的人;(尤指)悍妇
If you describe someone, especially a woman in a position of authority, as a tartar, you mean that they are fierce, bad-tempered, and strict.
3. see also: cream of tartar