assiduousness vs concentration

assiduousness and concentration both are nouns.

Word	Noun	Adjective	Verb	Adverb
assiduousness	Yes	No	No	No
concentration	Yes	No	No	No

As nouns, assiduousness and concentration are synonyms defined as:

assiduousness and concentration: great and constant diligence and attention

Other synonyms of assiduousness include assiduity.

assiduousness (noun)	concentration (noun)
great and constant diligence and attention	strengthening the concentration (as of a solute in a mixture) by removing diluting material
	bringing together military forces
	great and constant diligence and attention
	the strength of a solution; number of molecules of a substance in a given volume
	the spatial property of being crowded together
	complete attention; intense mental effort
	increase in density