Endlessly harass for brooch (5)
I believe the answer is:
badge
'brooch' is the definition.
The answer and definition can be both to do with contact as well as being verbs in their base form.
Perhaps you can see an association between them that I don't see?
'endlessly harass' is the wordplay.
'endlessly' means to remove the last letter.
'harass' becomes 'badger' (synonyms).
'badger' with its final letter taken away is 'BADGE'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for badge that I've seen before include "Shield" , "Thing worn to show, say, membership of organisation" , "Symbol worn, to indicate membership perhaps" , "Identifying sign" , "Worn emblem" .)