Delighted Conservative, left outside (7)
I believe the answer is:
excited
'delighted conservative left outside' is the definition.
'excited' can be an answer for 'delighted' (thesaurus). I'm unsure of the 'conservative left outside' bit.
'delighted conservative left outside' is the wordplay.
'delighted conservative' becomes 'c' (UK political abbreviation. I am not sure about the 'delighted' bit.).
'left' becomes 'exited' (to exit is to leave or depart).
'outside' means one lot of letters goes inside another.
'c' going into 'exited' is 'EXCITED'.
(Other definitions for excited that I've seen before include "moved by emotion" , "in high spirits" , "Agog" , "Animated" , "Feeling a pleasant tension" .)