is only a preposition

No, “only” is not a preposition. It can function as different parts of speech depending on its usage:

1. Adverb – Most commonly used to modify a verb, adjective, or another adverb.
   • Example: I only eat vegetables. (Modifies the verb “eat”)
   • Example: This is only a test. (Modifies the noun “test”)
2. Adjective – Used to describe a noun.
   • Example: He was the only person there. (Describes “person”)
3. Conjunction – Used to mean “but” or “except that.”
   • Example: I would go, only I’m too tired. (Similar to “but I’m too tired”)

It is not a preposition because prepositions typically show relationships between nouns, pronouns, and other words in a sentence (e.g., in, on, at, by, with).