Composer with sign of hesitation -- piece could be removed from here (7)
I believe the answer is:
holster
'piece could be removed from here' is the definition.
(piece can refer to a firearm)
'composer with sign of hesitation' is the wordplay.
'composer' becomes 'holst' (Gustav Holst).
'with' means one lot of letters go next to another.
'sign of hesitation' becomes 'er'.
'holst'+'er'='HOLSTER'
(Other definitions for holster that I've seen before include "that carries a gun" , "Gun holder" , "Gun case" , "Sheath for a handgun" , "Pistol-holder" .)