Powerful body’s miserable cop-outs (7)
I believe the answer is:
octopus
'powerful body's' is the definition.
'miserable cop-outs' is the wordplay.
'miserable' indicates anagramming the letters (I've seen this in other clues).
'cop'+'outs'='copouts'
'copouts' anagrammed gives 'OCTOPUS'.
(Other definitions for octopus that I've seen before include "Eight-legged creature" , "Mollusc with long tentacles" , "Sea creature's tentacles served as food" , "Tentacled marine mollusc" , "Eight-armed mollusc" .)