Tease a bit unfairly (4)
I believe the answer is:
bait
'tease' is the definition.
('bait' can be a synonym of 'tease')
'a bit unfairly' is the wordplay.
'unfairly' indicates anagramming the letters (I've seen this in other clues).
'a'+'bit'='abit'
'abit' is an anagram of 'BAIT'.
(Other definitions for bait that I've seen before include "Allurement" , "Worms, for example" , "Food on a hook to attract fish" , "Boilie, for example" , "Taunt; enticement" .)