Mean and smart, the ultimate in foxy (6)
I believe the answer is:
stingy
'mean' is the definition.
('stingy' can be similar in meaning to 'mean')
'smart the ultimate in foxy' is the wordplay.
'smart' becomes 'sting' (stinging is a kind of smarting).
'the ultimate in' indicates one should take the final letters.
The last letter of 'foxy' is 'y'.
'sting'+'y'='STINGY'
'and' acts as a link.
(Other definitions for stingy that I've seen before include "Close" , "near" , "Mean, tight" , "like a bee" , "Painful" .)