It is a verb
Meaning: To formally resign, renounce or relinquish the highest post or position of authority. This term is used only when the person is resigning on his/her own wish. It is also refers to, disowning a family member like disinheriting of a son.
Words with similar meaning: renounce, give up, abandon, surrender, relinquish, waive, forgo, abnegate
Other verb forms:
Present Tense: I/You/We/They abdicate , he/she/it abdicates
-ing form : abdicating
Past Simple and Past participle: abdicated
King Edward abdicated his throne in 1986.