Old-fashioned gent might come over from Rome. (4)
I believe the answer is:
cove
'old-fashioned gent might' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'come over from rome' is the wordplay.
'come over' shows that the letters should be reversed in order (I've seen 'coming over' mean this).
'from' becomes 'e' (I've seen this in other clues).
'rome' becomes 'voc' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'e'+'voc'='evoc'
'evoc' in reverse letter order is 'COVE'.
Can you help me to learn more?
(Other definitions for cove that I've seen before include "Small inlet or slang man" , "sheltered recess at Lulworth?" , "Rum fellow found in a small inlet" , "Small sheltered inlet" , "A small sea inlet or slangy man" .)