assiduity vs concentration

assiduity and concentration both are nouns.

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

As nouns, assiduity and concentration are synonyms defined as:

Other synonyms of assiduity include assiduousness.

assiduity (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