One gets really involved in play’s opening scene, but not its last (8)
I believe the answer is:
activist
'one' is the definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
'really involved in play's opening scene but not its last' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'its' is 'ist' which is within the answer.
'play' could be 'act' (synonyms) and 'act' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
'gets' acts as a link.
Can you help me to learn more?
(Other definitions for activist that I've seen before include "Advocate for action" , "Human dynamo" , "forceful person" , "Cause promoter" , "Committed campaigner" .)