Harass endlessly to get emblem (5)
I believe the answer is:
badge
'emblem' is the definition.
(badge is a kind of emblem)
'harass endlessly' is the wordplay.
'harass' becomes 'badger' (synonyms).
'endlessly' means to remove the last letter.
'badger' with its last letter taken off is 'BADGE'.
'to get' acts as a link.
(Other definitions for badge that I've seen before include "Emblem signifying rank, membership etc" , "Emblem of belonging" , "evidence of membership" , "Form of identification" , "One cheating others with fictitious schemes" .)