Syrup army doctor’s given girls (8)
I believe the answer is:
molasses
'syrup' is the definition.
(I've seen this before)
'army doctor's given girls' is the wordplay.
'army doctor' becomes 'mo'.
'given' is a charade indicator (letters next to each other).
'girls' becomes 'lasses' (lass is a kind of girl).
'mo'+'lasses'='MOLASSES'
(Other definitions for molasses that I've seen before include "Dark syrup extracted from sugar cane" , "Slow runner" , "sticky food" , "US name for treacle" , "what refinement can bring" .)