There’s nothing in port, perhaps, for soldiers (5)
I believe the answer is:
troop
'soldiers' is the definition.
(thesaurus)
'there's nothing in port perhaps' is the wordplay.
'there's' is a charade indicator (letters next to each other).
'nothing in' becomes 'o' (I've seen this in other clues).
'perhaps' indicates an anagram.
'o' next to 'port' is 'oport'.
'oport' with letters rearranged gives 'TROOP'.
'for' is the link.
(Other definitions for troop that I've seen before include "Group of, eg, monkeys" , "Large group (of soldiers?)" , "herd" , "Military unit" , "Cavalry unit commanded by a captain" .)