Grammar Point
suffix
suf 
~さ

-ness

nominalizing suffix indicating degree or condition

い-Adjective stem + さ

The suffix さ is attached to the stem of an adjective to transform it into a noun. This noun typically represents a measurable degree, a state, or a condition.

Adjective stem + さ

To form this, remove the final い from an い-Adjective and add さ. For な-Adjectives, simply add さ to the stem (the part without な).

The height of that mountain is surprising.

I do not know the depth of this lake.

The importance of health is clear.

Note

いい (good) is an exception and changes to よさ. This suffix is generally used for objective, measurable qualities like height, weight, or depth, though it can also describe subjective states.

Words: 
さ
Radicals of radicals