To arrogate is to take over. When the teacher steps out of the classroom and some bossy student marches up to the chalkboard and begins scolding the other kids? The student is trying to arrogate the teacher's authority.
To assume, or claim as one's own, unduly, proudly, or presumptuously; to make undue claims to, from vanity or baseless pretensions to right or merit; 
Verb
 seize and take control without authority and possibly with force; take as one''s right or possession; "He assumed to himself the right to fill all positions in the town"; "he usurped my rights"; "She seized control of the throne after her husband died"
Verb
 demand as being one''s due or property; assert one''s right or title to; "He claimed his suitcases at the airline counter"; "Mr. Smith claims special tax exemptions because he is a foreign resident"
Verb
 make undue claims to having
v. t.
 To assume, or claim as one's own, unduly, proudly, or
   presumptuously; to make undue claims to, from vanity or baseless
   pretensions to right or merit; as, the pope arrogated dominion over
   kings.
Arrogate
He arrogated to himself the right of deciding dogmatically what was orthodox doctrine.
To assume, or claim as one's own, unduly, proudly, or presumptuously; to make undue claims to, from vanity or baseless pretensions to right or merit; 
Usage Examples
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