Finally going for a tryst involving university degree-holder (8)
I believe the answer is:
graduate
'degree-holder' is the definition.
(university graduate)
'finally going for a tryst involving university' is the wordplay.
'finally going for' becomes 'gr' (I can't justify this - if you can you should give a lot more credence to this answer).
'tryst' becomes 'date' (a tryst is a romantic date).
'involving' indicates putting letters inside.
'university' becomes 'u' (abbreviation for university).
'date' placed around 'u' is 'duate'.
'gr'+'a'+'duate'='GRADUATE'
(Other definitions for graduate that I've seen before include "University type" , "Holder of an academic degree" , "Person with a college degree" , "Move to the next stage" , "University alumnus" .)