Minister voted in, Conservatives are reticent initially (5)
I believe the answer is:
vicar
'minister' is the definition.
(a religious minister)
'voted in conservatives are reticent initially' is the wordplay.
'initially' suggests taking the first letters.
The initial letters of 'voted in conservatives are reticent' is 'VICAR'.
(Other definitions for vicar that I've seen before include "See stand-in" , "Member of the clergy" , "Oliver Goldsmith wrote 'The . . . . . of Wakefield'" , "Parish clergyman" , "one brought in for service?" .)