tirelessvstirelesslyTell them apart

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

Which to use

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

#27,678
“tireless” frequency rank
#26,282
“tirelessly” frequency rank
53960
confusion score

Side-by-Side Comparison

Feature tireless tirelessly
Definition Indefatigable, untiring and not yielding to fatigue In a tireless manner; without tiring, flagging, or ceasing.

Letter map: tireless vs tirelessly

Shared letters muted; letters that set tireless and tirelessly apart highlighted. Shared run: 8. tireless runs 8 letters (CVCVCVCC) against tirelessly's 10 (CVCVCVCCCV) - the length gap alone is often enough to separate them once you know to check it.

8 ch
tireless
10 ch
tirelessly

Role in the sentence - tireless and tirelessly

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: tireless is anadjective and tirelesslyanadverb. On the page they differ by 2 extra letter(s) - “tireless” sits inside “tirelessly”. Our composite confusion score for this pair is 53960, derived from the frequency rank of both members and their visual similarity.

tireless is recorded at frequency rank #27,678, classified as anadj. tirelessly is at rank #26,282, tagged as anadv.

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 53960, this pair ranks #144,817 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of tireless vs tirelessly

Shared letters: eilrst. Private to "tireless": -. Private to "tirelessly": y.

"tireless" · 8 letters · shape CVCVCVCC  ·  "tirelessly" · 10 letters · shape CVCVCVCCCV

Known mistypes of this pair

  • tireless ← itreless · tierless · tireelss · tireles · tirelless · tirelses · tirleess · tirreless
  • tirelessly ← itrelessly · tierlessly · tireelssly · tireleslsy · tirelesly · tirelesslly · tirelesslyy · tirelessyl

Frequently Asked Questions

Can "tireless" and "tirelessly" be used interchangeably?
No - they are not even the same part of speech. "tireless" is an adjective and "tirelessly" an adverb, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "tireless" or "tirelessly"?
"tirelessly" is the more common of the two: it sits at frequency rank #26,282 in our English list, against #27,678 for "tireless". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

After this comparison

Pair "tireless" vs "tirelessly" is on the table, pick a follow-up below.

  • Full dictionary entry for "tireless" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "tirelessly" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #144,817 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "tireless" and "tirelessly" also get mixed up with nearby pairs, the highest-scored neighbour is "tiredness vs tireless". 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 #144,817 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