Etymology From Middle English -ouste, from Old French -ouseté, from Latin -ōsitās; later modified to the current form. It is equivalent to -ose or -ous + -ity.
1
Morpheme Forming nouns, usually abstract, and usually from adjectives in -ous or -ose.
2
Colloquial, Morpheme Forming nouns from other adjectives for humorous effect.