Europe's tallest active volcano (4)
I believe the answer is:
etna
'europe's tallest active volcano' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for etna that I've seen before include "Neat volcano overturned" , "high peak" , "smoker in Sicily" , "Heating vessel" , "hotly-tipped runner" .)