A person whose whereabouts are unknown and who is being sought.

(chiefly military) The designation for a member of an organization (usually military) with whom contact is lost and whose whereabouts are not known, but whose death is not confirmed.

(idiomatic) A perfect, ideal or suitable female mate or wife.

(colloquial) A hypothetical primate once thought necessary to explain a perceived evolutionary gap between apes and humans. / (figuratively) Any sought-after or valuable intermediary figure or position.

(now chiefly US) Inconsistent, unpredictable, erratic; sometimes succeeding and sometimes failing.

(now chiefly UK) Alternative form of hit-or-miss

(of a projectile) To fail to hit the target. / (figuratively) To fail to achieve the intended result.

To miss an experience or lose an opportunity, etc. that should not be missed. / (chiefly Britain) To leave out, to omit.

(intransitive) To fail to take advantage of an opportunity; to overlook or be too late to pursue an option or course of action.

To allow an advantageous opportunity to pass by.