Self-control or restraint—the ability or act of restraining desires or impulses; controlling one's emotions or behavior.
ダイエット中は自制が必要だ。
You need self-control when dieting.
彼は怒りを抑える自制心がある人だ。
He is someone who has the self-discipline to hold back his anger.
自制が利かずに余計な一言を言ってしまった。
Lacking self-control, I said an unnecessary remark.