Volunteers a kiss as tribute (3)
I believe the answer is:
tax
'tribute' is the definition.
(thesaurus)
'volunteers a kiss' is the wordplay.
'volunteers' becomes 'TA' (abbreviation for Territorial Army).
'a kiss' becomes 'x' (X can represent a kiss).
'ta'+'x'='TAX'
'as' is the link.
(Other definitions for tax that I've seen before include "Impose levy or burden on" , "Government levy" , "Payment to the Exchequer" , "Be trying" , "Tariff" .)