1. Constant in application or attention; devoted; attentive.
2. Performed with constant diligence or attention; unremitting; persistent; as, “assiduous labor.”
But he was a man who by assiduous reading, through his devotion to literature, had become the quintessential successful gentleman, a man who could hold his own with the most cultivated companions.
— Milton Gould, quoted in “For Cooke, a Lasting Memorial,” by Peter Finn and Richard Justice, Washington Post, April 11, 1997
Defection, recreancy; If someone is accused of apostasy, they are accused of abandoning their religious faith, political loyalties, or principles.
Rel: Apostate, n. A person who has rejected her religious or political ideals.