known quantity

someone whose character, personality, and behavior are recognized and understood. We need not worry about how John will behave. He is a known quantity. Lisa is a known quantity and I am sure she will not surprise us by voting with the opposition.

Common Names:

Name	Pronounced	Usage
Sami (1)	SAH-mee	Finnish
Enid	['i:nid]
Gage	GAYJ	English (Modern)
Laci (1)	-	Hungarian
Driscoll	DRIS-kəl	English (Rare), Irish
Lyon	['laiən]