Octopus arm (8)
I believe the answer is:
tentacle
'octopus arm' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tentacle that I've seen before include "Long, boneless limb in some animals" , "Flexible appendage on some animals" , "Slender flexible limb" , "Part of octopus" , "Octopus's limb" .)