Angriest when provoked, one won't react and isn't noble (5,3)
I believe the answer is:
inert gas
'one won't react and isn't noble' is the definition.
I can't judge whether this defines the answer.
'angriest when provoked' is the wordplay.
'when provoked' indicates an anagram (I've seen this in other clues).
'angriest' with letters rearranged gives 'INERT GAS'.
Can you help me to learn more?
(Other definitions for inert gas that I've seen before include "Eg, krypton or argon" , "He, amongst others" , "Eg, helium, xenon etc." , "One expects no reaction from such" , "He perhaps" .)