- not propitious
- adverse, contrary, or disadvantageous
- Likely to be a hindrance; disadvantageous: unfavorable winds.
- Having or showing opposition; adverse: an unfavorable reaction to our proposal.
(comparative more unfavorable, superlative most unfavorable)
- Nouns to which "unfavorable" is often applied: condition, circumstance, weather, climate, outcome, result, opinion, view, impression, effect, consequence, impact, influence, environment, balance, information, report, prognosis, rating, evaluation, review, position, factor, feature, aspect, reaction, response, attitude, season, development, treatment, ruling, case, state, experience, inference.
un- + favourable