An unfavorable situation or circumstance
drawback, disadvantageousness, weak point, impediment, inconvenience, stumbling block, detriment, downside, liability, obstacle, bar, handicap, disability, limitation, inexpedience, undesirableness, unsatisfactoriness, hindrance, objection, problem, failing, weakness, difficulty, trouble, snag, lack; harmful circumstance, adverse circumstance, disadvantageous circumstance, unfortunate circumstance, damaging circumstance, etc.; ineffectiveness, fault, defect, deficiency, imperfection, inadequacy, negative; see also impediment 1, restraint 2, weakness 2.
Antonyms advantage*, benefit, effectiveness.