Loudly breaking nail last (5)
I believe the answer is:
final
'last' is the definition.
(I know that last can be written as final)
'loudly breaking nail' is the wordplay.
'loudly' becomes 'f' (short for forte - 'loud' in music).
'breaking' indicates an anagram.
'nail' with letters rearranged gives 'inal'.
'f'+'inal'='FINAL'
(Other definitions for final that I've seen before include "Concluding" , "big match" , "The last exam or leg of competition" , "Not to be altered" , "Conclusive" .)