Musician rips off cracking headgear (7)
I believe the answer is:
harpist
'musician' is the definition.
(I know that harpist is a type of musician)
'rips off cracking headgear' is the wordplay.
'off' indicates an anagram.
'cracking' is an insertion indicator (inserted letters go into a gap or crack).
'headgear' becomes 'hat' (hat is a kind of headgear).
'rips' with letters rearranged gives 'rpis'.
'rpis' inserted within 'hat' is 'HARPIST'.
(Other definitions for harpist that I've seen before include "Instrumentalist" , "musician" , "Stringed instrument player" .)