"The Untouchables" hero (4)
I believe the answer is:
ness
'the untouchables hero' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ness that I've seen before include "Headland, cape" , "Eliot -, led effort against Al Capone; Scots loch" , "Scottish loch - headland" , "Famous loch" , "Headland, promontory" .)