ASSID'UOUS, adjective [Latin assiduus, from assideo, to sit close, ad and sedeo; Eng. to sit.] 1. Constant in application; as a person assiduous in his occupation. 2. Attentive; careful; regular in attendance; as an assiduous physician or nurse. 3. Performed with constant diligence or attention; as assiduous labor.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI