The difference between Dexter and Sinister

When used as adjectives, dexter means right, whereas sinister means inauspicious, ominous, unlucky, illegitimate (as in bar sinister).

Dexter is also noun with the meaning: the right side of a shield from the wearer's standpoint, and the left side to the viewer.

check bellow for the other definitions of Dexter and Sinister

Dexter as a noun (heraldry):

The right side of a shield from the wearer's standpoint, and the left side to the viewer.
Dexter as a noun:

The right hand.

Sinister as an adjective:

Inauspicious, ominous, unlucky, illegitimate (as in bar sinister).
Sinister as an adjective:

Evil or seemingly evil; indicating lurking danger or harm.

Examples:

"sinister influences"

"the sinister atmosphere of the crypt"
Sinister as an adjective:

Of the left side.
Sinister as an adjective (heraldry):

On the left side of a shield from the wearer's standpoint, and the right side to the viewer.
Sinister as an adjective (obsolete):

Wrong, as springing from indirection or obliquity; perverse; dishonest.