Is WHISS a Wordle Word?

Yes. WHISS is a valid Wordle word.

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

What does WHISS mean?

Obsolete form of whiz: To make a whirring or hissing sound, similar to that of an object speeding through the air.“Their fatal bullets whissed, the green sward dyed, The horses reared and plunged in maddening pain, br> And stumbling, fell upon the crimson plain.”

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

Starter word rating: WeakIn the top 95% of all valid Wordle words for testing common letters.
Vowels: I
Unique letters: 4 of 5Repeats S
Common letters: I

Hard-mode trap: 10 valid words fit the pattern WHI_S. 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.