Party leader's extremely snazzy, stylish and spiritual (7)
I believe the answer is:
psychic
'spiritual' is the definition.
(thesaurus)
'party leader's extremely snazzy stylish' is the wordplay.
'party leader' becomes 'p' (I've seen this in other clues).
'extremely' suggests removing the centre.
'stylish' becomes 'chic' ('chic' can be similar in meaning to 'stylish').
'snazzy' with its middle removed is 'sy'.
'p'+'sy'+'chic'='PSYCHIC'
'and' acts as a link.
(Other definitions for psychic that I've seen before include "Clairvoyant" , "Spiritualistic medium" , "Telepathic?" , "One is apparently sensitive to things beyond the rest of us" , "One is apparently sensitive to the paranormal" .)