A formal, somewhat literary expression equivalent to やむを得ない. Used to state that a situation is inevitable or beyond one's control. Often appears in written or formal spoken contexts.
See also: やむを得ない
In this situation, a postponement cannot be helped.
Delays due to the accident are unavoidable.
Variant using 止む for やむ; less common but attested.
Derived from the classical negative volitional form of やむを得ない (止むを得ない), literally 'there is no way to stop it'. The まい ending is an archaic negative volitional auxiliary, giving the expression a formal, literary feel.