プログレッシブ和英中辞典(第4版)の解説
いちいち【一一】
❶〔一つ一つ〕one by one
それをいちいち数え上げたらきりがない
If you start counting them one by one, there will be no end to it.
❷〔ことごとく〕
いちいち文句を言うな
Don't find fault with everything.
❸〔詳しく〕in detail
いちいち説明しなくてよい
You needn't 「explain in detail [go into detail].