Genuine University student accepted a bill upfront (6)
I believe the answer is:
actual
'genuine' is the definition.
(synonyms)
'university student accepted a bill upfront' is the wordplay.
'university' becomes 'u'.
'student' becomes 'l' (as in L-plates for learner drivers).
'accepted' indicates putting letters inside.
'bill' becomes 'act' (I've seen this in other clues).
'upfront' means one lot of letters go next to another (some letters go in front of others).
'u'+'l'='ul'
'ul' placed around 'a' is 'ual'.
'ual' put after 'act' is 'ACTUAL'.
(Other definitions for actual that I've seen before include "De facto" , "Concrete, tangible" , "Real and existing (6)" , "Real, existent" , "Real, genuine" .)