Meet with success in the vale (8)
I believe the answer is:
farewell
'vale' is the definition.
('vale' means farewell in Latin)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for farewell that I've seen before include "vale" , "Say goodbye" , "Parting word" , "Departure" , "It may be said when 15" .)