noun
Refers to the speech disfluency itself. It is a sensitive term, so use with care.
See also: 吃音
彼はどもりがあって、話すのに時間がかかる。
He has a stutter and takes time to speak.
noun
stammerer; stutterer
Refers to a person who stammers or stutters. Also sensitive; avoid using it to label someone casually.
子供の頃、どもりだったけど、今はほとんど気にならない。
I was a stutterer as a child, but now it hardly bothers me.
吃音 is a more clinical or formal term for stuttering, while どもり is the everyday word.
Derived from the verb どもる (to stammer), with the nominalizing suffix り. The kanji 吃 is used for its meaning 'to stammer', but the word is native Japanese.