Is SINKY a Wordle Word?

Yes. SINKY is a valid Wordle word.

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

What does SINKY mean?

/ˈsɪŋki/

Into which one can sink.“Then I settled myself in the roomiest, deepest, sinkiest of spring-cushioned “arm-chairs,” and fastened my gaze on him, to wander no more while he stayed.”

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

Starter word rating: WeakIn the top 71% of all valid Wordle words for testing common letters.
Vowels: I
Unique letters: 5 of 5
Common letters: I

Hard-mode trap: 9 valid words fit the pattern _INKY. 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.