Sacks left empty and back to front of service (5)
I believe the answer is:
table
'service' is the definition.
(synonyms)
'sacks left empty and back to front' is the wordplay.
'sacks' indicates an anagram (I've seen 'sack' mean this (sack can mean destroy or spoil)).
'front' indicates taking the first letters.
The first letters of 'left empty and back to' is 'leabt'.
'leabt' anagrammed gives 'TABLE'.
'of' is the link.
(Other definitions for table that I've seen before include "Food stand or numbers array" , "counter" , "Chart; present formally" , "League --; multiplication --" , "Working, eating, surface" .)