言わずもがな

Consisting of 言わず (“not saying”) +‎ も (“even if”) +‎ がな (“particle used to indicate the speaker's hope, desire, wish”)

言(い)わずもがな • (iwazumogana) 

1. not even saying would be preferable (because not expressing it at all would be better)

   言(い)わずもがなのことを言(い)う

   iwazumogana no koto o iu

   saying unnecessary things (that would be better if left unsaid)

2. needless to say, not to mention, obvious (because it is already known)

   Synonym: 言うまでも無い

   子供(こども)は言(い)わずもがな、大人(おとな)まで騒(さわ)ぎ出(だ)した。

   Kodomo wa iwazumogana, otona made sawagidashita.

   Even the adults were panicking, not to mention the children.