Visitors to Sicily should see it before coming back (4)
I believe the answer is:
etna
'visitors to sicily should see it' is the definition.
I can't tell whether this defines the answer.
'before coming back' is the wordplay.
'before' becomes 'ante' (prefix meaning 'before').
'coming back' says the letters should be written in reverse.
'ante' in reverse letter order is 'ETNA'.
Can you help me to learn more?
(Other definitions for etna that I've seen before include "It could erupt" , "Europe's highest active volcano" , "Volcano; reverse of stake" , "Italian smoker" , "feature spewing lava" .)