Protection, for example, accepted by Mafiosi from time to time (5)
I believe the answer is:
aegis
'protection' is the definition.
(aegis can mean someone's guidance or protection)
'example accepted by mafiosi from time to time' is the wordplay.
'example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'accepted by' means one lot of letters goes inside another (inserted letters are accepted).
'from time to time' indicates alternate letters (letters removed on a regular basis).
The alternate letters of 'mafiosi' are 'ais'.
'eg' going into 'ais' is 'AEGIS'.
'for' acts as a link.
(Other definitions for aegis that I've seen before include "Protection (originally of Zeus)" , "shelter" , "Auspices" , "Protection - patronage" , "Custody" .)