Shame was mine and yours, initially (4)
I believe the answer is:
pity
'shame' is the definition.
(I know that shame can be written as pity)
'mine and yours initially' is the wordplay.
'mine' becomes 'pit' (as in a mining pit).
'and' is a charade indicator (letters next to each other).
'initially' says to take the initial letters.
The first letter of 'yours' is 'y'.
'pit'+'y'='PITY'
'was' is the link.
(Other definitions for pity that I've seen before include "true compassion?" , "Feel sorrow for" , "Sympathy for others" , "Sympathy and sorrow" , "Sympathise with" .)