Loophole gives viewer permit (6)
I believe the answer is:
eyelet
'loophole' is the definition.
(thesaurus)
'viewer permit' is the wordplay.
'viewer' becomes 'eye' (I've seen this before).
'permit' becomes 'let' ('let' can be a synonym of 'permit').
'eye'+'let'='EYELET'
'gives' is the link.
(Other definitions for eyelet that I've seen before include "Small hole for lace, etc" , "Small hole as in needle or shoe" , "A lace is passed through it" , "Hole for fastener" , "Small opening in shoe for lace" .)