Is RIFFS a Wordle Word?

Yes. RIFFS is a valid Wordle word.

It is not on the Wordle answer list, so it is unlikely to be a daily answer.

Plurals ending in S are almost never chosen as Wordle answers.

What does RIFFS mean?

A repeated instrumental melody line in a song.“Listen to one of the greatest guitar riffs of all time!”
A clever or witty remark.
A variation on something.

1 more noun definition

To improvise in the performance or practice of an art, especially by expanding on or making novel use of traditional themes.
To riffle.

Definition from Wiktionary, available under the CC BY-SA license.

Starter word rating: WeakIn the top 78% of all valid Wordle words for testing common letters.
Vowels: I
Unique letters: 4 of 5Repeats F
Common letters: R, I

Hard-mode trap: 9 valid words fit the pattern _IFFS. If you reach it, you may need several guesses to find the last letter.

Letter ratings use how often each letter appears in Wordle answers.

Tap its tiles to the colours Wordle showed, and the Wordle Solver lists every word that still fits, with the best next guess.