Meaning & use
rock-hard
Last updated
Meanings
adjectivenot comparable
Extremely hard and solid, like a rock; very difficult to break or press.
Grammar: Used after linking verbs like be, feel, become: The ground felt rock-hard.
Patterns
- be rock-hard
- feel rock-hard
- become rock-hard
After the frost, the soil was rock-hard and impossible to dig.
The bread had been left out for days and was rock-hard.
He slept on a rock-hard floor and woke up stiff.
adjectivenot comparable
Extremely firm and strong, especially of muscles or a body part.
Grammar: Often used to describe abs or muscles that feel very tight and solid.
Patterns
- rock-hard abs
- rock-hard muscles
- rock-hard body
He does a hundred sit-ups every morning and now has rock-hard abs.
Her legs were rock-hard from years of cycling.
The trainer promised that after a month I would have a rock-hard stomach.
adjectivenot comparablefigurative
Very determined and unlikely to change; inflexible.
Grammar: Used figuratively for attitudes or positions that are firmly fixed.
Patterns
- rock-hard attitude
- rock-hard position
- rock-hard determination
She took a rock-hard position against the new policy.
His rock-hard determination helped him finish the marathon.
The negotiators were rock-hard and refused to compromise.
Common combinations
- rock-hard ground
- The rock-hard ground made planting impossible.
- rock-hard abs
- After months of training, he showed off his rock-hard abs.
- rock-hard muscles
- The boxer had rock-hard muscles from years of training.
- rock-hard determination
- Her rock-hard determination inspired the whole team.
Synonyms and how they differ
- stone-hard
- Very similar, but less common and slightly more literary; rock-hard is more everyday.
- solid
- Means firm and not liquid or gas, but can be less extreme than rock-hard; solid wood is hard but not rock-hard.
- unyielding
- Formal and often used for people or materials that do not give way; rock-hard is more physical and informal.
Opposites
Commonly confused: rock-hard or hard as a rock?
rock-hard vs hard as a rock
A simile meaning the same, but it is a phrase, not a single adjective; rock-hard is more compact and often used before nouns.
Practice
Choose the correct sentence.
Choose one answer.
Rock-hard is an adjective that does not have comparative or adverb forms, so it stays the same. The other options wrongly add -ly or -er/-est.
Make it your own
Write a sentence using “rock-hard”, then check it and compare it with the examples above.