It may be collectively interesting, whether or not to us (5)
I believe the answer is:
curio
'it may be collectively interesting whether or not to us' is the definition.
The definition suggests a singular noun which matches the answer.
This is the entire clue.
Can you help me to learn more?
(Other definitions for curio that I've seen before include "odd thing" , "Rare and unusual item" , "Something unusual, perhaps worthy of collecting" , "Antique" , "Small fascinating collectible object" .)