Left religious painting unfinished in covered entrance (7)
I believe the answer is:
portico
'covered entrance' is the definition.
(I've seen this before)
'left religious painting unfinished' is the wordplay.
'left' becomes 'port' (left side of a ship - opposite of starboard).
'religious painting' becomes 'icon' (I've seen this before).
'unfinished' means to remove the last letter.
'icon' with its final letter taken off is 'ico'.
'port'+'ico'='PORTICO'
'in' is the link.
(Other definitions for portico that I've seen before include "Roofed porch" , "A number of columns" , "gallery, perhaps" , "building construction" , "Covered walkway" .)