What part of speech is stymies?

Stymies can be categorized as a noun and a verb.

Parts of speech

1. stymies is a verb, present, 3rd person singular of stymie (infinitive).
2. stymies is a noun, plural of stymie.

Verb
stymy - hinder or prevent the progress or accomplishment of; "His brother blocked him at every turn"
Noun
stymy - a thwarting and distressing situation
stymy - a situation in golf where an opponent's ball blocks the line between your ball and the hole