Sole Liberal in west end of Oklahoma City (4)
I believe the answer is:
only
'sole' is the definition.
(synonyms)
'liberal in west end of oklahoma city' is the wordplay.
'liberal' becomes 'l' (abbreviation).
'in' means one lot of letters goes inside another.
'west end of' says to take the initial letters (the leftmost letter of the word).
'city' becomes 'ny' (I've seen this in other clues).
The initial letter of 'oklahoma' is 'o'.
'o'+'ny'='ony'
'l' inserted inside 'ony' is 'ONLY'.
(Other definitions for only that I've seen before include "And nothing more; sole" , "Existing alone with no other, perhaps a child" , "Unique; merely" , "And no one else" , "Except that; single" .)