Arthropod (6)
I believe the answer is:
insect
'arthropod' is the definition.
(I know that insect is a type of arthropod)
This is all the clue.
(Other definitions for insect that I've seen before include "Contemptible person" , "Nicest (anag) - six-footer" , "Fly, say?" , "Bug" , "Imago" .)