Viewer allowed to get in a hole (6)
I believe the answer is:
eyelet
'hole' is the definition.
(hole for putting a shoelace through)
'viewer allowed to' is the wordplay.
'viewer' becomes 'eye' (organ which sees or views).
'allowed to' becomes 'let' (to let something happen is to allow it).
'eye'+'let'='EYELET'
'get in a' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for eyelet that I've seen before include "Small opening in needle for thread" , "Hole in needle through which thread passes" , "Small hole through which lace passes" , "Hole in shoe through which lace passes" , "Small lace-hole in shoe (6)" .)