Huckleberry ___ (4)
I believe the answer is:
finn
'huckleberry' is the definition.
(Huckleberry Finn in novels by Mark Twain)
This is all the clue.
(Other definitions for finn that I've seen before include "hero of American fiction" , "eg Sibelius" , "National" , "Someone from Helsinki?" , "Trollope's Phineas; one from Tampere" .)