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"Sir" is a form of "sir", a noun which is often translated as "el señor". "Really" is an adverb which is often translated as "muy". Learn more about the difference between "sir" and "really" below.
sir()
A noun is a word referring to a person, animal, place, thing, feeling, or idea (e.g., man, dog, house).
really()
An adverb is a word that describes a verb, an adjective, or other adverbs (e.g., to run quickly, very tired).
1. (very)
An interjection is a short utterance that expresses emotion, hesitation, or protest (e.g., Wow!).
