What is the meaning of Niceness?

Silliness; folly.

Effeminacy; indulgence in soft living or luxuriousness.

Shyness; reserve.

Fastidiousness; fine sensitivity.

Pleasantness, especially of behaviour or personality; agreeableness.

A value determining how much processor time to concede to a running process. (See also nice (verb), renice.)

Source: wiktionary.org