いちいち
いちいち · ichiichi · JLPT N2 · noun
one
☝️☝️ いち = one, said twice: one, one, one at a time
いち is the Japanese word for one (一), and doubling it gives 一々: one and then one, going through each item separately. In everyday speech it often has a fussy edge, as in commenting on every single little thing.