Noun: Represents a person, place, thing, or idea (e.g., "cat," "London," "happiness")
Pronoun: Takes the place of a noun to avoid repetition (e.g., "he," "she," "it," "they")
Verb: Expresses an action or state of being (e.g., "run," "think," "is")
Adjective: Describes or modifies a noun (e.g., "red," "happy," "big")
Adverb: Describes or modifies a verb, adjective, or other adverb, typically answering questions like "how," "when," "where," or "to what degree" (e.g., "quickly," "very," "here")