In fact, a long claw (5)
I believe the answer is:
talon
'claw' is the definition.
(talon is a kind of claw)
'in fact a long' is the wordplay.
'in' indicates the answer is hidden within the clue.
'TALON' is hidden in the letters of 'fact a long'.
(Other definitions for talon that I've seen before include "Claw of a bird of prey" , "One may be grabbing" , "ogee moulding" , "Raptor's claw" , "Holding part of flier" .)