Is SITHE a Wordle Word?

Yes. SITHE is a valid Wordle word.

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

What does SITHE mean?

/saɪð/

Obsolete spelling of scythe: An instrument for mowing grass, grain, etc. by hand, composed of a long, curving blade with a sharp concave edge, fastened to a long handle called a snath.“[…]and, whatever thing the sithe of time mows down, devour unspared.”
Alternative spelling of sith: A journey, way.
A sigh.

Obsolete spelling of scythe: An instrument for mowing grass, grain, etc. by hand, composed of a long, curving blade with a sharp concave edge, fastened to a long handle called a snath.
To journey, travel, wayfare.
To sigh.“c1475, The Macro Plays, Mankindː I may both sithe and sob; this is a piteous remembrance”

Alternative spelling of sith (“since”).“Wherefore (O kyng) I speake as one for all, / Sithe all as one do beare you egall faith:”

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

Starter word rating: AverageIn the top 12% of all valid Wordle words for testing common letters.
Vowels: I, E
Unique letters: 5 of 5
Common letters: I, T, E

Hard-mode trap: 7 valid words fit the pattern _ITHE. 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.