“+ transitive verb
Etymology: un- (II) + seat
1. : to dislodge from one's seat especially on horseback
gave up horseback riding when a low-hanging limb unseated him
2.
a. : to displace in a political rank or office usually by an elective process
defeated an attempt … to unseat him in the primary — Current Biography
party caucus that unseated the Old Guard regime — New York Times
b. : to remove or depose from rank or office by legal action or force
by a close vote … declined to unseat him — C.A.Berdahl
had been unseated for bribery — J.A.Froude
in his second army coup … unseated the president of the island republic — Current Biography