* Noun: A drop of salty liquid that comes from your eye when you cry. *Example:* A single tear rolled down her cheek.
* Verb: To rip or pull apart. *Example:* She tore the paper in half.
* Verb: To move quickly or suddenly. *Example:* The car tore off down the road.
So, to know which part of speech "tear" is, you need to look at the context of the sentence.