Fellow with jewel, but wanting Liberal leadership (8)
I believe the answer is:
hegemony
'leadership' is the definition.
(thesaurus)
'fellow with jewel but wanting liberal' is the wordplay.
'fellow' becomes 'he' ('he' refers to a man).
'with' is a charade indicator (letters next to each other).
'jewel' becomes 'gem' (synonyms).
'but wanting liberal' becomes 'ony' (I can't justify this - if you can you should believe this answer much more).
'he'+'gem'+'ony'='HEGEMONY'
Can you help me to learn more?
(Other definitions for hegemony that I've seen before include "Dominance of one state over another" , "Leadership, superior influence" , "Leadership, dominance" , "Preponderant influence" , "Dominant position" .)