-ity

(Latin: suffix used to form abstract nouns expressing act, state, quality, property, or condition corresponding to an adjective)

homogeneity
Similar throughout; of uniform structure or composition.
homozygosity
The state of possessing a pair of identical alleles at a given locus.
humanity
1. Human beings as a group.
2. The quality, condition, or fact of being human; humanness.
hyperacuity
The increased sharpness of sense perceptions.
hyperadiposis
An extreme degree of adiposis, or fatness.
hypoacidity
Deficiency of acid; lack of normal acidity, as of the gastric juice.
hypoacuity
Decreased sharpness of sense perception.
idiomaticity
The quality or state of being idiomatic.
inability
Lack of ability, capacity, means, or power.
inalterable (adjective), more inalterable, most inalterable
Relating to anything that is not possible to change or to modify.
incredulity
1. A disbelieving frame of mind; unreadiness or unwillingness to believe (statements, etc.); disbelief.
2. A state or feeling of disbelief.

There are two ways to slide easily through life; to believe everything or to doubt everything; both ways save us from thinking.

—Alfred Korzybski
inequilibrium (s) (noun), inequilibriums, inequilibria (pl)
That which is unbalanced because of opposing forces being uneven.
infecundity (s) (noun), infecundities (pl)
An unfruitfulness; barrenness; a female sterility.
infinity (s) (noun), infinities (pl)
1. Unlimited space, time, distance, quantity, etc.; extending beyond any measure or comprehension; without beginning or end; endless: Beyond the Earth we find infinity.
2. Very great; vast; immense: such as, space or time: Outer space provides an infinity of stars.
3. In mathematics, the concept of being unlimited by always being larger than any imposed value or boundary: Infinity exists beyond or is greater than any arbitrarily large value.
4. In photography, a distance setting, as on a camera, beyond which the entire field is in focus: Shirley set the lens on her camera to infinity so objects at a distance would be in focus.
inhumanity
1. Lack of pity or compassion.
2. An inhuman or cruel act.