Disadvantage
Drawback
Synonyms Drawback, downside, catch, fly in the ointment, weakness, defect, handicap, trouble, problem, liability, hindrance, impediment, minus, spanner in the works, snag, stumbling block, pitfall, weak spot/point, flaw, fault, limitation, difficulty, complication, nuisance, obstacle, disbenefit, hiccup, and monkey wrench in the works.
Treat unfavourably
Synonyms Treat unfavourably, treat harshly/unfairly, inflict a handicap on, be unfair to, put at a disadvantage, handicap, do a disservice to, and wrong.
Example Sentences
The disadvantage is hard to ignore.
This decision has a disadvantage.
He faced a significant disadvantage.
Lack of experience is a disadvantage.