As nouns the difference between noiselessness and tranquility
is that noiselessness is the quality or state of being noiseless; quiet or hush while tranquility is an alternative spelling of lang=en.
noiselessness
English
Noun
(-)
the quality or state of being noiseless; quiet or hush
tranquility
English
Noun
(en-noun)
Usage notes
* More common spelling in the US; less common in the UK.