(countable and uncountable, plural nicenesses)
- Effeminacy; indulgence in soft living or luxuriousness. [from 16th c.]
- Fastidiousness; fine sensitivity. [from 17th c.]
- Pleasantness, especially of behaviour or personality; agreeableness. [from 19th c.]
- (computing, Unix) A value determining how much processor time to concede to a running process. (See also nice (verb), renice.)
From nice + -ness.