1. 不祥的：oblige迫使 | ominous不祥的 | outcry强烈抗议
2.
2. 恶兆的：omen 预兆 | ominous 恶兆的 | ominously 恶兆地
3. 不吉利的：obsequious#顺从的;逢迎的 | ominous#不吉利的 | inquisitive#好奇的
1. 不祥的；恶兆的；不吉利的
If you describe something as ominous, you mean that it worries you because it makes you think that something unpleasant is going to happen.
e.g. There was an ominous silence at the other end of the phone...
电话那头出现了不祥的沉默。
e.g. The rolls of distant thunder were growing more ominous.
远处隆隆的雷声听着愈发惊心，要变天了。