つきな月並tsukinamiつきなみ月次tsukinamiげつじ月次getsuji
1.

Referring to something that occurs or is done every month, implying a sense of regularity or routine.

2.

Characterized by a lack of originality or creativity; often used to describe ideas, expressions, or actions that are common and unremarkable.

Example:

月並みのパーティーだったよ。