Force offering amnesty from time to time (3)
I believe the answer is:
met
'force' is the definition.
(I've seen this in other clues)
'amnesty from time to time' is the wordplay.
'from time to time' indicates alternate letters (letters removed on a regular basis).
The alternate letters of 'amnesty' are 'MET'.
'offering' acts as a link.
(Other definitions for met that I've seen before include "gathered together" , "Encountered pro tem" , "Made a connection" , "London police (abbr) - New York Museum of Art (abbr)" , "Got together" .)