noun
voluntary insurance; optional insurance
Insurance taken out by choice, not legally required. Often refers to optional vehicle insurance beyond the mandatory 強制保険 (compulsory insurance).
See also: 強制保険
自動車の任意保険に加入するかどうか迷っている。
I'm unsure whether to take out voluntary car insurance.
任意保険は強制保険より補償範囲が広い。
Voluntary insurance has broader coverage than compulsory insurance.