Difference between Ominous and Unpropitious

OMINOUS vs UNPROPITIOUS: ADJECTIVE

Specifically, giving indication of a coming ill; being an evil omen; threatening; portentous; inauspicious.
Of or pertaining to an omen or to omens; being or exhibiting an omen; significant; portentous; -- formerly used both in a favorable and unfavorable sense; now chiefly in the latter; foreboding or foreshowing evil; inauspicious.
Of or being an omen, especially an evil one.
Menacing; threatening.
Threatening or foreshadowing evil or tragic developments
Presaging ill-fortune

Of ill omen; giving indication of coming ill; portentous; inauspicious; unlucky.
Of good omen; auspicious.
Conveying some omen; serving as a sign or token; significant.

Eerie, Grim, Unsettling, Minacious, Ill, Forbidding, Threatening, Unpropitious, Minatory, Ugly, Inauspicious, Baleful, Sinister, Alarming, Menacing

Unpredicted, Momentous, Dicey, Unpredictable, Portentous, Disastrous, Fortuitous, Calamitous, Perilous, Unpromising, Propitious, Ill, Thunderous, Inauspicious, Ominous

Eerie, Grim, Unsettling, Minacious, Ill, Forbidding, Threatening, Unpropitious, Minatory, Ugly, Inauspicious, Baleful, Sinister, Alarming, Menacing

Unpredicted, Momentous, Dicey, Unpredictable, Portentous, Disastrous, Fortuitous, Calamitous, Perilous, Unpromising, Propitious, Ill, Thunderous, Inauspicious, Ominous

But almost immediately they ran into ominous opposition.
There was nothing but ominous silence from Kolanse.
SYN: Predictive, ominous, portentous, premonitory, fatidical, oracular, sibylline.
The reports produced by these teams were ominous.
The chiefs had regarded that as particularly ominous.
Lena notices other, ominous signs, though, and sheworries.
One other resignation had even more ominous overtones.
This evasion, however, is the less ominous option.
Polyhydramnios and fetal intrauterine growth restriction: ominous combination.
We heard an ominous hiss from the kitchen.

Europe, and consequently, when the seasons are not too unpropitious, they display the hardiness and distinction characteristic of northern products.
There has been probably no time in our history which has been more unpropitious for such a project.
Not the haughty heirs of distinguished names more than the humble sons of obscurity and unpropitious fortune.
Great Britain would be an event unpropitious to the interests of this Union.
But his father, forsaking that trade, took to farming at an unpropitious time.