Late Middle English; earliest use found in Boccaccio's De Claris Mulieribus. From classical Latin calliditāt-, calliditās cleverness, skill, craftiness, cunning from callidus + -tās.
Definition of callidity in US English:
callidity
nounkəˈlɪdɪti
rare
Craftiness, cunning; shrewdness.
Origin
Late Middle English; earliest use found in Boccaccio's De Claris Mulieribus. From classical Latin calliditāt-, calliditās cleverness, skill, craftiness, cunning from callidus + -tās.