It's possibly mean of us to show delight (7)
I believe the answer is:
enamour
'delight' is the definition.
(I've seen this before)
'it's possibly mean of us' is the wordplay.
'it's possibly' is an anagram indicator.
'of us' becomes 'our' (I've seen this before).
'mean' anagrammed gives 'enam'.
'enam'+'our'='ENAMOUR'
'to show' is the link.
(Other definitions for enamour that I've seen before include "Delight" , "Charm, captivate" , "sweep one off one's feet" , "Inspire with love; charm" , "Enchant" .)