はいわずもがなだ (wa-iwazu-mogana): Needless to say; not to mention
～はいわずもがなだ (wa-iwazu-mogana)
Meaning
Needless to say; not to mention
Formation and usage
N + は言わずもがな
Notation: N = noun; V dictionary = dictionary-form verb; V stem = the stem before ます; plain clause = plain-form clause; negative stem = the form before ない. Follow the attachment shown above.
Explanation
Treats A as obvious before extending to B; in a different construction it can mean something better left unsaid.
Examples
会議には、学生は言わずもがな、教員も参加した。
Students of course attended the meeting, and teachers did too.
試験には、学生は言わずもがな、教員も参加した。
Students of course attended the exam, and teachers did too.
研修には、学生は言わずもがな、教員も参加した。
Students of course attended the training session, and teachers did too.
発表会には、学生は言わずもがな、教員も参加した。
Students of course attended the presentation event, and teachers did too.
面接には、学生は言わずもがな、教員も参加した。
Students of course attended the interview, and teachers did too.
How related patterns differ
なり～なり suggests alternatives; といわず～といわず encompasses all cases. は言わずもがな treats the first as obvious. てはばからない openly acts without restraint; ときたら often complains. つ～つ mainly occurs in fixed verb pairs.