* Adjective: Describing something that is neat and organized (e.g., "The house was tidy.")
* Verb: Meaning to put things in order (e.g., "I need to tidy my room.")
* Noun: A person who is neat and organized (e.g., "She's a real tidy.")
So, to know what part of speech "tidy" is, you need to consider the context of the sentence it appears in.