inside joke

a joke that only certain people understand; a joke understood only by people who know certain facts and context. What you said must be an inside joke. It makes no sense to me.

Common Names:

Name	Pronounced	Usage
Mario	MAH-ryo (Italian, Spanish)	Italian, Spanish, Croatian
Timothei	-	Old Church Slavic
Haywood	['heiwud]
Ingrid	['iŋgrid]
Harper	HAHR-pər	English
Woodall	['wudəl]