Roman playwright in time before on one occasion expressing love (7)
I believe the answer is:
terence
'roman playwright' is the definition.
(I've seen this before)
'in time before on one occasion expressing love' is the wordplay.
'in time' becomes 't' (abbreviation. I am not sure about the 'in' bit.).
'before' becomes 'ere' (usually literary).
'on one occasion' becomes 'once' (synonyms).
'expressing' indicates named letters should be taken away.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'once' with 'o' taken out is 'nce'.
't'+'ere'+'nce'='TERENCE'
Can you help me to learn more?
(Other definitions for terence that I've seen before include "Roman comic dramatist" , "Stamp" , "old comic" , "A man" , "guy" .)