unfavorable (adj.)

also unfavourable, mid-15c. (implied in unfavorably), from un- (1) "not" + favorable (adj.).

"We must not indulge in unfavorable views of mankind, since by doing it we make bad men believe that they are no worse than others, and we teach the good that they are good in vain." [Walter Savage Landor, "Imaginary Conversations"]