abdicator

transitive verb, intransitive verb abdicated -·cat′ed, abdicating -·cat′·ing

1. to give up formally (a high office, throne, authority, etc.)
2. to surrender or repudiate (a right, responsibility, etc.)

Etymology: < L abdicatus, pp. of abdicare, to deny, renounce < ab-, off + dicare, to proclaim, akin to dicere, to say: see diction