sinisterly

adjective

1. 1. Archaic on, to, or toward the left-hand side; left
   2. Heraldry on the left side of a shield (the right as seen by the viewer)
2. threatening harm, evil, or misfortune; ominous; portentous: sinister storm clouds
3. wicked, evil, or dishonest, esp. in some dark, mysterious way: a sinister plot
4. most unfavorable or unfortunate; disastrous: met a sinister fate