expression, i-adjective
too many to count; innumerable
Used when examples, reasons, or things are so numerous that listing them all would be endless. Often appears in formal or written contexts.
彼の失敗は枚挙にいとまがない。
His mistakes are too many to count.
この問題の原因は枚挙にいとまがないほどある。
There are so many causes of this problem that they are innumerable.
A more common and casual way to say 'countless'; 枚挙にいとまがない is more formal and often used in written language.
From 枚挙 (listing one by one) + に + いとまがない (have no leisure/time). Literally 'there is no time to list them one by one', meaning too numerous to enumerate.