expression, adverb
this and that; one thing or another
Used almost exclusively in the phrase 四の五の言う (or 四の五の言わず) to mean complaining or nitpicking about trivial things. The standalone adverbial use is rare.
See also: 四の五の言わず
四の五の言わずに、さっさと宿題をやりなさい。
Stop complaining about this and that and just do your homework.
彼はいつも四の五の文句を言っている。
He's always griping about one thing or another.