Jealous of endless souvenir exchange (7)
I believe the answer is:
envious
'jealous' is the definition.
(I know that jealous can be written as envious)
'endless souvenir exchange' is the wordplay.
'endless' means to remove the last letter.
'exchange' indicates anagramming the letters.
'souvenir' with its final letter taken away is 'souveni'.
'souveni' anagrammed gives 'ENVIOUS'.
'of' acts as a link.
(Other definitions for envious that I've seen before include "Grudging of others" , "Green, in emotion" , "Covetous, jealous" , "Begrudging another's fortune" , "Full of jealousy" .)