Bound to get left on shelf (5)
I believe the answer is:
ledge
'shelf' is the definition.
(synonyms)
'bound to get left' is the wordplay.
'bound' becomes 'edge' (synonyms).
'to get' is a charade indicator (letters next to each other).
'left' becomes 'L' (common abbreviation).
'edge' after 'l' is 'LEDGE'.
'on' acts as a link.
(Other definitions for ledge that I've seen before include "rocky situation?" , "Narrow projecting shelf as from window" , "Projecting shelf, horizontal projection" , "Sill" , "Ridge or shelf" .)