In the sentence, the word "early" describes when the action of going for practice occurred. Since it modifies the verb "went" by providing information about the time, it functions as an adverb.
Nouns are words for people, places, things, or ideas (e.g., morning, practice).
Verbs are action words or states of being (e.g., went).
Adjectives describe nouns (e.g., early morning—here, "early" is an adjective modifying the noun "morning").
Adverbs describe verbs, adjectives, or other adverbs by answering questions like how, when, where, or to what extent (e.g., went early).
