Formally admit (6)
I believe the answer is:
induct
'formally admit' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for induct that I've seen before include "Bring or lead in as for initiation" , "Formally admit (to a post or organisation)" , "Accept into an exclusive society or group" , "Introduce" , "Admit as a member" .)