Philanthropist seen heading off fiddling with cigar (8)
I believe the answer is:
carnegie
'philanthropist' is the definition.
(I've seen this before)
'seen heading off fiddling with cigar' is the wordplay.
'heading off' means to remove the first letter.
'fiddling with' indicates anagramming the letters.
'seen' with its first letter taken off is 'een'.
'een' anagrammed with 'cigar' makes 'CARNEGIE'.
(Other definitions for carnegie that I've seen before include "Nice gear (anag) - Scottish-American philanthropist" , "Andrew ..., famous American philanthropist" , "Andrew ........, Scottish philanthropist; or New York concert Hall" , "US philantropist who endowed libraries" , "US philanthropist who endowed libraries" .)