noun, adverb
all alone; by oneself
Emphasizes being completely alone, with no one else present. Often used adverbially.
See also: 一人きり
彼は一人っきりで部屋にいた。
He was all alone in the room.
一人っきりで旅行するのが好きだ。
I like traveling by myself.
Emphatic form of 一人きり (hitorikiri), with gemination (っ) adding colloquial emphasis. きり derives from 切り (cut off, limit), implying 'only' or 'just'.