Ominous
Sinister, Bad Luck, Ill Omen
noun, な adjective
Something that is not good luck is ominous and sinister. It's also bad luck and an ill omen.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
すごく不吉な夢を見たもんで、あんたのことが心配になってこうして電話をした訳さ。
I had such an ominous dream that it made me really worried about you, and that’s why I called.