Difference between Sinister and Ominous

SINISTER vs OMINOUS: ADJECTIVE

Unlucky; inauspicious; disastrous; injurious; evil; -- the left being usually regarded as the unlucky side.
Situated on or being the side of a shield on the wearer's left and the observer's right.
On the left side; left.
Attended by or causing misfortune or disaster.
Portending misfortune or disaster; ominous.
Causing or intending harm or evil; wicked.
Suggesting or threatening harm or evil.
Threatening or foreshadowing evil or tragic developments
Stemming from evil characteristics or forces; wicked or dishonorable
On the left hand, or the side of the left hand; left; -- opposed to dexter, or right.
Wrong, as springing from indirection or obliquity; perverse; dishonest; corrupt.
On or starting from the wearer's left
See under Bar, n.
An appearance of two planets happening according to the succession of the signs, as Saturn in Aries, and Mars in the same degree of Gemini.
See under Escutcheon.
Inauspicious, ominous, unlucky, illegitimate (as in bar sinister).
Evil or seemingly evil; indicating lurking danger or harm.
Of the left side.
On the left side of a shield from the wearer's standpoint, and the right side to the viewer.
Indicative of lurking evil or harm; boding covert danger.

Presaging ill-fortune
Threatening or foreshadowing evil or tragic developments
Menacing; threatening.
Of or being an omen, especially an evil one.
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.
Specifically, giving indication of a coming ill; being an evil omen; threatening; portentous; inauspicious.

Malicious; evil; base; wrong.
Unpleasant; disagreeable.
Bringing evil; harmful; malign; unfortunate in results.
On or toward the left or unlucky side; hence, of ill omen; inauspicious; threatening or suggesting evil.
Left, as opposed to right; on the left side; specifically, in heraldry, noting the left-hand side of the person who carries the shield on his arm (therefore the right-hand side of the spectator): the sinister part of the escutcheon is opposed to the dexter part (see dexter).
Wicked or dishonorable

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.

Nefarious, Minacious, Threatening, Black, Sinistral, Forbidding, Ugly, Alarming, Dark, Baleful, Wicked, Minatory, Menacing, Ominous, Evil

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

Nefarious, Minacious, Threatening, Black, Sinistral, Forbidding, Ugly, Alarming, Dark, Baleful, Wicked, Minatory, Menacing, Ominous, Evil

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

These proposals have no sinister purpose at all.
Both have a vague hint of sinister punishment.
The crowd responds violently and with sinister intent.
This song oozes sex appeal and sinister intention.
Like this extending a tight boss by means of a sinister side of the yours with the until your sinister ear.
For example, if enemy leads Mister Sinister you will want to use Ultron because Sinister will clone Ultron spawns most of the time.
Sinister in the face to get him where she wants him, but Sinister seems to like it!
Many myths and legends speak of dark and sinister figures and sinister, magical acts deep in the woods.
If Mister Sinister is an ally, transfer all positive effects from the primary target to Mister Sinister.
The backcountry Marlow travels through is sinister, and the natives become more sinister as well.

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.