The place, ‘room’, ‘lieu’, or function (of a person or thing) as held by a substitute or a… to keep (a person's) stead: to be (his) deputy, act on…

intransitive. To act as a deputy or substitute.

intransitive. To act as a deputy. colloquial.

intransitive. To take the place of something; to act as a replacement for.

intransitive. To take the place of another in a position, role, or job, usually temporarily; to deputize or act as a substitute for (a person); spec.…

intransitive. To act as a representative for.