noun
inside joke; private joke; in-joke
Refers to a joke or understanding shared only within a closed group, often not funny to outsiders. Can also imply a private agreement or favor among insiders.
彼らの会話は内輪受けのネタばかりで、私にはさっぱりわからなかった。
Their conversation was full of inside jokes, and I couldn't understand it at all.
その冗談は完全に内輪受けだった。
That joke was completely an inside joke.
Compound of 内輪 (uchiwa, 'private, family circle') and 受け (uke, 'reception, popularity'). The exact historical derivation is uncertain, but the term naturally describes humor or agreements that are well-received only within a limited group.