intransitive. To officiate at a wrestling match or other contest; to act as a referee. Hence more generally: to act as a mediator; to intercede or…

In contextual uses, with ellipsis of complement. intransitive. Cricket. To act as umpire on the cricket field.

intransitive. To officiate or act as a referee.

intransitive. To act as umpire. Also const. between, betwixt.

transitive and intransitive = referee, v. 1.