Plastic plate a bad design (9)
I believe the answer is:
adaptable
'plastic' is the definition.
(thesaurus)
'plate a bad design' is the wordplay.
'design' indicates anagramming the letters.
'plate'+'a'+'bad'='plateabad'
'plateabad' anagrammed gives 'ADAPTABLE'.
(Other definitions for adaptable that I've seen before include "Able to be modified" , "having different uses?" , "Suitable for new situation or use" , "Able to adjust to new conditions" , "Able to adjust to circumstances" .)