Customs exist within Gibraltar, if foreign (6)
I believe the answer is:
tariff
'customs' is the definition.
(thesaurus)
'within gibraltar if foreign' is the wordplay.
'within' indicates the answer is hidden within the clue.
'TARIFF' is hidden within 'gibraltar if foreign'.
'exist' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for tariff that I've seen before include "Tax or duty on a class of imports" , "Tax or duty to be paid on some imports or exports" , "List of fixed charges as in hotel" , "Duty; table of charges" , "List of duties on imports or exports" .)