What does "-ness" mean at the end of an adjective? — Fabio, Colombia
When you add "-ness" to an adjective, it becomes a noun. The suffix "-ness" means "state : condition : quality" and is used with an adjective to say something about the state, condition, or quality of being that adjective.
For example, redness is a red quality, and redness means "the quality of being red."
The redness in his eyes went away after he got some sleep.
Bitterness is a bitter condition, or "the condition of being bitter."
The breakup caused them to feel anger and bitterness.
Sleepiness means "the condition of being sleepy."
Her sleepiness made it difficult for her to pay attention in class.
Weightlessness is a weightless quality.
She was happy about the weightlessness of her new luggage.
Inquisitiveness means "the state of being inquisitive."
The inquisitiveness of the puppy caused him to get into trouble sometimes.
Bashfulness means "the state of being bashful." Friendliness means "the state of being friendly."
The bashfulness of the new student soon became friendliness.
Not all adjectives can be made into nouns using "-ness." Typically, if an adjective is in its -er or -est form, "-ness" cannot be added: higher and highest cannot become higherness or highestness. Typically, if an adjective is actually a participle of a verb, "-ness" cannot be added: washed and running cannot become washedness or runningness. Most other adjectives, however can be made into nouns by adding "ness."