a.

1. 恶意的，阴险的，邪恶的
   a sinister smile

   奸笑

   A sinister expression appeared on his face when I called him a liar.

   当我称他为骗子时，他的脸上出现了一个凶恶的表情。

2. 凶兆的，不祥的
3. 不幸的，灾难性的
   a sinister fate

   厄运

4. 左边的；在左边的[Z]

adj.

1. suggestive of evil or harm.
2. archaic & Heraldry  on or towards the left-hand side (in a coat of arms, from the bearer's point of view, i.e. the right as it is depicted). The opposite of dexter¹.