Is HARTS a Wordle Word?

Yes. HARTS 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 HARTS mean?

A muscular organ that pumps blood through the body, traditionally thought to be the seat of emotion.
Emotions, kindness, moral effort, or spirit in general.“The team lost, but they showed a lot of heart.”
The seat of the affections or sensibilities, collectively or separately, as love, hate, joy, grief, courage, etc.; rarely, the seat of the understanding or will; usually in a good sense; personality.“a good, tender, loving, bad, hard, or selfish heart”

9 more noun definitions

Courage; courageous purpose; spirit.
Vigorous and efficient activity; power of fertile production; condition of the soil, whether good or bad.
A term of affectionate or kindly and familiar address.“Listen, dear heart, we must go now.”
Personality, disposition.“a cold heart”
A wight or being.
A conventional shape or symbol used to represent the heart, love, or emotion: ♥ or sometimes <3.
A playing card of the suit hearts featuring one or more heart-shaped symbols.
The twenty-fourth Lenormand card.
The centre, essence, or core.“Buddhists believe that suffering is right at the heart of all life.”

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

Starter word rating: AverageIn the top 11% of all valid Wordle words for testing common letters.
Vowels: A
Unique letters: 5 of 5
Common letters: A, R, T

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