* Noun: "Teasing" can refer to the act of teasing itself, often used in phrases like "He was known for his teasing."
* Verb: "Teasing" is the present participle of the verb "to tease," which means to playfully or annoyingly make fun of someone. For example, "She was teasing him about his new haircut."
To determine which part of speech it is in a sentence, consider its context and function.