In dishonest way, lay fur in slyly (8)
I believe the answer is:
unfairly
'in dishonest way' is the definition.
(in an unfair or dishonest manner)
'lay fur in slyly' is the wordplay.
'slyly' indicates an anagram.
'lay'+'fur'+'in'='layfurin'
'layfurin' anagrammed gives 'UNFAIRLY'.
(Other definitions for unfairly that I've seen before include "Inequitably, wrongly" , "Without justice" , "Unjustly" , "dishonestly" .)