Some fearless nobleman (4)
I believe the answer is:
earl
'nobleman' is the definition.
(member of the nobility)
'some fearless' is the wordplay.
'some' indicates a hidden word (some parts of the word are used).
'EARL' is hidden within 'fearless'.
(Other definitions for earl that I've seen before include "Male equivalent of a countess" , "Rank below marquess" , "Jimmy Carter's middle name" , "... Grey, fragrant Oriental tea" , "Real (anag) - nobleman" .)