an éminence grise

(formal)

someone who has a lot of power and influence but no official position Although he never became a minister, he was the party's éminence grise for 15 years.

Common Names:

Name	Pronounced	Usage
Abiram	ə-BIE-rəm (English)	Biblical
SØLvi	-	Norwegian
FÉLix	FE-leeks (Portuguese)	French, Spanish, Portuguese
Kassia	KA-shə	English (Rare)
Desmond	['dezmənd]
Ozzy	AHZ-ee	English