grey matter

(British & Australian humorous) also gray matter (American humorous)

your intelligence It's an entertaining film but it doesn't exactly stimulate the old grey matter.

Name	Pronounced	Usage
Montse	-	Catalan
Blanch	BLANCH	English
Bohumila	-	Czech
Missy	MIS-ee	English
Hokolesqua	-	Native American, Shawnee
Vanessa	[və'nesə]