tirednessvstirelessWhich spelling fits?

Quick tell: tiredness is a noun, tireless is an adjective, so they fill different roles in a sentence.

Which to use

“tiredness” is a noun and “tireless” is an adjective - they look or sound alike but fill different roles in a sentence.

#32,211
“tiredness” frequency rank
#27,678
“tireless” frequency rank
59889
confusion score

Side-by-Side Comparison

Feature tiredness tireless
Definition The state of being tired. Indefatigable, untiring and not yielding to fatigue

Letter map: tiredness vs tireless

Shared letters muted; letters that set tiredness and tireless apart highlighted. Shared run: 7. tiredness runs 9 letters (CVCVCCVCC) against tireless's 8 (CVCVCVCC) - the length gap alone is often enough to separate them once you know to check it.

9 ch
tiredness
8 ch
tireless

Role in the sentence - tiredness and tireless

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: tiredness is anoun and tirelessanadjective. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 59889, derived from the frequency rank of both members and their visual similarity.

tiredness is recorded at frequency rank #32,211, classified as anoun. tireless is at rank #27,678, tagged as anadj.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 59889, this pair ranks #103,460 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of tiredness vs tireless

Shared letters: eirst. Private to "tiredness": dn. Private to "tireless": l.

"tiredness" · 9 letters · shape CVCVCCVCC  ·  "tireless" · 8 letters · shape CVCVCVCC

Known mistypes of this pair

  • tiredness ← itredness · tierdness · tirdeness · tireddness · tiredenss · tirednes · tirednness · tirednses
  • tireless ← itreless · tierless · tireelss · tireles · tirelless · tirelses · tirleess · tirreless

Frequently Asked Questions

Can "tiredness" and "tireless" be used interchangeably?
No - they are not even the same part of speech. "tiredness" is a noun and "tireless" an adjective, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "tiredness" vs "tireless" - which ranks higher?
"tireless" is the more common of the two: it sits at frequency rank #27,678 in our English list, against #32,211 for "tiredness". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Done with this confusable. These links stay specific to "tiredness" and "tireless".

  • Full dictionary entry for "tiredness" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "tireless" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #103,460 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "tiredness" and "tireless" also get mixed up with nearby pairs, the highest-scored neighbour is "tireless vs tirelessly". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #103,460 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list