Equality inspires leaders on official list in opposition (8)
I believe the answer is:
polarity
'opposition' is the definition.
(I know that polarity is a type of opposition)
'equality inspires leaders on official list' is the wordplay.
'equality' becomes 'parity' (parity is a kind of equality).
'inspires' indicates putting letters inside (inspire means to breathe in).
'leaders on' says to take the initial letters.
The initial letters of 'official list' is 'ol'.
'parity' enclosing 'ol' is 'POLARITY'.
'in' acts as a link.
(Another definition for polarity that I've seen is " It is positive or negative".)