As′si‐du″i‐ty (�), n.; pl.Assiduities (�). [L. assiduitas: cf. F. assiduite. See Assiduous.] 1. Constant or close application or attention, particularly to some business or enterprise; diligence.
I have, with much pains and assiduity, qualified myself for a nomenclator.
Addison.
2. Studied and persevering attention to a person; — usually in the plural.