Acid destroying visor core (9)
I believe the answer is:
corrosive
'acid' is the definition.
(thesaurus)
'destroying visor core' is the wordplay.
'destroying' indicates an anagram.
'visor'+'core'='visorcore'
'visorcore' is an anagram of 'CORROSIVE'.
(Other definitions for corrosive that I've seen before include "Destroying by chemical action" , "Hurtful" , "Caustic, erosive" , "Caustic and destructive" , "Able to eat away" .)