Alone; by oneself; being or acting without anyone else's help (often used with 〜で as in 自分一人で).
自分一人で引っ越しをするつもりだ。
I plan to move by myself.
夜道を自分一人で歩くのは少し不安だ。
I'm a bit uneasy walking alone on a dark street.
その仕事は自分一人で最後までやり遂げた。
I completed that task on my own.