What does the prefix REALLY mean?

The prefix "REALLY" doesn't actually exist in English as a standalone prefix. It's typically used as an intensifier or an adverb meaning truly, very, or extremely.

Here's a breakdown:

* Intensifier: "Really" intensifies the meaning of the adjective or adverb it modifies. For example: "That's really cold!"

* Adverb: "Really" can modify verbs, adjectives, or other adverbs. For example: "I really like your new shoes."

It's important to note: "Really" isn't a prefix like "un-" or "pre-". It functions as a separate word on its own.