Tending to contradict or oppose, contrarious.
That contradicts something, such as an argument.
That is diametrically opposed to something.
That is itself a contradiction.
Mutually exclusive.
Either of a pair of propositions, that cannot both be true or both be false.
Serving to hinder or oppose; adverse, disadvantageous, inconducive, unsuitable.
Of wind or weather: causing delay or obstacles; not conducive to travel or work; inclement.
Of a belief, state of mind, etc.: not favourable; disapproving.
Not auspicious; ill-boding.