Admit to office son gets tiresome briefly (5,2)
I believe the answer is:
swear in
'admit to office' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for swear in that I've seen before include "Get into office" , "prepare to deliver evidence" , "Administer official oath" , "Induct into office" , "Administer oath to one taking up office" .)