Chief competitor, not right to be concerned with records (8)
I believe the answer is:
archival
'chief' is the definition.
Although both the answer and definition are adjectives, I cannot understand how one could define the other.
'competitor not right to be concerned with records' is the wordplay.
I cannot really understand how this works, but
'right' could be 'ar' (I've seen this in other clues) and 'ar' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for archival that I've seen before include "records?" , "Record-keeping" , "describing record collection" , "Like recordings" .)