Biased? Indeed so, unfortunately (3-5)
I believe the answer is:
one-sided
'biased?' is the definition.
(I know that biased can be written as one-sided)
'indeed so unfortunately' is the wordplay.
'unfortunately' indicates an anagram (a bad or unfortunate spelling).
'indeed'+'so'='indeedso'
'indeedso' anagrammed gives 'ONE-SIDED'.
(Other definitions for one-sided that I've seen before include "Unilateral" , "Indeed so (anag.)" , "Unfairly biased" , "So denied being unfair or biased" , "Unbalanced" .)