avidity n.

c. 1300, "inordinate desire of gaining and possessing wealth," fifth of the seven deadly sins, from Old French avarice "greed, covetousness" (12c.), from Latin avaritia "greed, inordinate desire," from avarus "greedy, grasping," adjectival form of avere "crave, long for, be eager," from Proto-Italic *awe- "to be eager," from PIE *heu-eh- "to enjoy, consume" (source also of Sanskrit avasa- "refreshment, food," avisya- "gluttony;" Welsh ewyllys "will;" Armenian aviwn "lust").

In Middle English it also was used of immoderate desire for knowledge, glory, power, etc., but it "has become limited, except in figurative uses, so as to express only a sordid and mastering desire to get wealth" [Century Dictionary].

"eager; greedy," 1769, from French avide (15c.), from Latin avidus "longing eagerly, desirous, greedy," from avere "to desire eagerly" (see avarice). Also in part a back-formation from avidity. Related: Avidly.