nothing special; not a big deal; insignificant
Used to dismiss something as trivial, unimportant, or not worth counting. Often appears in negative contexts to emphasize that something is negligible.
A mistake of this level is nothing to worry about.
To him, about a thousand yen is insignificant.
Standard kanji-kana spelling.
All-kana spelling, common in casual writing.
Literally 'it is not the number of things,' meaning something is so trivial it doesn't even count as a thing. The exact origin is uncertain, but it is a common idiomatic expression.