sleeplessness

noun

By · According to Wiktionary data (CC BY-SA) ·

"sleeplessness" is a 13-letter English headword indexed on PlainSpell.

The verdict

“sleeplessness” is uncommon English (frequency #67,051 among 6,566 “S” headwords), classed as a noun. The kind of spelling people second-guess.

#67,051
frequency rank, English
6,566
“S” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Lack of sleep; the property of being sleepless; the inability to sleep, insomnia.

Corpus desk

Index EN-sleeplessness · sleeplessness · English

sleeplessness · rank #67,051 · 0 variants · 0 confusables

  • FREQ-RARE #67,051
  • LEN-MEGA 13 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-DENSE 6,566
  • PHOTO-FINISH sleuthing

Nearest frequency peer: sleuthing (+1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Long-tail ranks near “sleeplessness”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “sleeplessness” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for sleeplessness
PropertyValue
Headwordsleeplessness
LanguageEnglish
Part of speechNoun
Letters13
Frequency rank#67,051
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “sleeplessness” in English

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right).sleeplessnessfalls in this rarity band:

#1#100#1K#10K#100K
← used constantlyrarely used →

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Rare peers in the same band: “sleuthing” (#67,052), “simp” (#67,049), “slumdog” (#67,053). Among 6,566 “S” headwords, “sleeplessness” is #67,051. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

sleeplessness is uncommon English at frequency #67,051 among 6,566 “S” headwords, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "Lack of sleep; the property of being sleepless; the inability to sleep, insomnia.".

We couldn't generate a plausible misspelling set for sleeplessness, a straightforward case of a spelling with little room for common typos. No close-neighbour confusable shows up for this headword in our dataset, which typically means the spelling is too distinctive to be mistaken for another word.

Etymologically, the entry records: From sleepless + -ness. The correct English form is sleeplessness, spelled S-L-E-E-P-L-E-S-S-N-E-S-S.

Definition

  1. 1
    Lack of sleep; the property of being sleepless; the inability to sleep, insomnia.

Etymology

From sleepless + -ness.

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "sleeplessness"?
"sleeplessness" is spelled S-L-E-E-P-L-E-S-S-N-E-S-S.
What does "sleeplessness" mean?
As a noun, "sleeplessness" means: Lack of sleep; the property of being sleepless; the inability to sleep, insomnia.
What is the origin of the word "sleeplessness"?
From sleepless + -ness. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "sleeplessness", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 13 letters (nearest by frequency rank).

shapeshifting#67,038Scientologist#67,027unrepresented#67,132prospectively#66,956

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

Source: FrequencyWords open word-frequency list