Sloshed con-man in tree (8)
I believe the answer is:
cinnamon
'tree' is the definition.
(cinnamon is a kind of tree)
'sloshed con-man in' is the wordplay.
'sloshed' is an anagram indicator.
'con'+'man'+'in'='conmanin'
'conmanin' anagrammed gives 'CINNAMON'.
(Other definitions for cinnamon that I've seen before include "Yellow-brown spice from bark of Asian tree" , "spicy stuff" , "Yellowish-brown - spice" , "The spice is oddly non-manic" , "'Spice in con man, strangely (8)'" .)