Questions & Answers about Ich bin heute etwas müde.
Etwas has two main uses:
As a pronoun = something
- Example: Ich habe etwas für dich. – I have something for you.
As an adverb = a bit / somewhat / rather
- Example (like your sentence): Ich bin heute etwas müde. – I’m a bit tired today.
In Ich bin heute etwas müde, etwas comes directly before an adjective (müde) and modifies its degree, so it must be the adverb a bit / somewhat, not the pronoun something (which would not fit grammatically or logically here).