Meaning of “swear sb in” - Learner’s Dictionary

swear sb in

phrasal verb with swear uk us /sweər/ verb (past tense swore, past participle sworn)

to make someone such as a president, judge, etc officially promise to be honest and responsible when they start their job:

[ often passive ] Mr Stein was sworn in as City Council president.

(Definition of “swear sb in” from the Cambridge Learner’s Dictionary © Cambridge University Press)