rock hard
"rock-hard" is a 8-letter English headword indexed on PlainSpell.
The verdict
“rock hard” is uncommon English (outside the top frequency list), classed as an adjective. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 9
- letters
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - As tough, hard, or inflexible as a piece of rock.
| Property | Value |
|---|---|
| Headword | rock hard |
| Language | English |
| Part of speech | Adjective |
| Letters | 9 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “rock hard” sits in English frequency
Rare enough to double-check
rock hard is uncommon English outside the top frequency list, classed as anadjective. Rarity is why readers land here mid-draft. 4 senses are on record.
rock hard doesn't appear in our generated misspelling index, typically a sign the spelling maps closely to how the word sounds. It is not paired with a close-neighbour confusable in our dataset, which typically means the spelling is too distinctive to be mistaken for another word.
This entry carries no recorded etymology, so its spelling is best read as a straightforward mapping from sound to letter. The correct English form is rock hard, spelled R-O-C-K- -H-A-R-D.
Definition
- 1As tough, hard, or inflexible as a piece of rock.
- 2With muscles developed and toned to a high degree, especially the muscles of the abdomen.
- 3Having a very fully erect and stiff penis
- 4With strongly held beliefs and opinions, deep conviction.
Synonyms
This word in other languages
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.
Frequently Asked Questions
How do you spell "rock hard"?
What does "rock hard" mean?
What language does "rock hard" come from?
Is PlainSpell free to use?
Using “rock hard”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is R-O-C-K- -H-A-R-D - every other letter order is a misspelling in standard orthography.
- Browse more English words and confusable pairs in the same reference. English words
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.