'Ness'

Not talking about the LOCH NESS monster😀 

The suffix 'ness' indicates 'a state of' when it forms a word, for example:
'weightlessness' derived from the adjective 'weightless'
'happiness' derived from the adjective 'happy'
'sadness' derived from the adjective 'sad'
'firmness' derived from the adjective 'firm'
'calmness' derived from the adjective 'calm'
and so on.
The first example in this list is an example of suffixes used in tandem, the first suffix is 'less' and the second is 'ness'.
There are several words like this:
'Listlessness' derived from 'listless'
'Restlessness' derived from 'restless'
'Carelessness' derived from 'careless', etc.