Cleanness vs Cleanliness

Question

I only heard "cleanness" for the first time yesterday - I did not know this word existed.

So what's the difference between cleanness and cleanliness?

I've read this http://forum.wordreference.com/showthread.php?t=973672 but am not clear when I would use "cleanness"

Answer 1

It might help to consider that, on the one hand, cleanliness is derived from the dated adjective cleanly, which means

(of a person or animal) habitually clean and careful to avoid dirt.

^{— Oxford Dictionaries}

On the other hand, cleanness is derived from the adjective clean, which has the following basic meanings:

1. free from dirt, marks, or stains:
2. morally uncontaminated; pure; innocent:
3. free from irregularities; having a smooth edge or surface:

^{— Oxford Dictionaries (Visit for elaboration on various meanings and usage)}

The word cleanness can thus be used in any of the senses of the word, clean, in reference to people, places, things (inanimate and abstract e.g. buildings, sounds, etc.), actions, and so forth. Also, note that cleanliness can only be used for people or animals.

Answer 2

Quoting from The Learner’s Dictionary:

Cleanliness is a much more common word than cleanness. They look similar and are certainly related.

But cleanness is usually used to refer to the senses of clean that have to do with shape, appearance, or impression (such as "pleasingly simple" and "having edges that are straight and smooth"):

The cleanness, tidiness, and manageability of city life kept surprising her.

…the bareness, cleanness, and sobriety of Doric architecture.

The performance showed all the technical exactitude and cleanness of tone that earlier music demands.

Cleanliness refers to being clean or not messy or dirty:

The restaurant's kitchen is regularly inspected for cleanliness.

His habits of personal hygiene and cleanliness were learned in the army.

She was much concerned with the cleanliness of public bathrooms.