-ity

turns an adjective or root into a noun naming a state or quality

Spelled -ity, -ty · -itas, -tat- 'state or quality'

Latin -itas named a state or quality: serenity is calmness, acuity is sharpness, and integrity is wholeness.

Words built from it

serenity — a state of calmness
seren- (calm) + -ity (state or quality)
acuity — sharpness of thought, sight, or hearing
acu- (sharp) + -ity (state or quality)
integrity — honesty and firm moral principles
integr- (whole or untouched) + -ity (state or quality)
adversity — hardship or an unfavorable condition
advers- (turned against) + -ity (state or condition)
brevity — shortness in time or expression
brev- (short) + -ity (state or quality)
ferocity — savage fierceness
feroc- (fierce) + -ity (state or quality)

-ism — turns an idea or practice into a noun naming a doctrine, system, practice, or characteristic behavior
-ist — turns a field, practice, or belief into a noun for a person associated with it
-ive — turns a verb or root into an adjective meaning tending to, able to, or serving to do it
-ize — turns a noun or adjective into a verb meaning make, become, or treat in that way
-less — turns a noun into an adjective meaning without or lacking it