1520s, of persons, "fickleness;" 1610s, of things, "mutability, irregularity," from Latin inconstantia "inconstancy, fickleness," abstract noun from inconstans "changeable, inconsistent" (see inconstant).
Entries linking to inconstancy
inconstant adj.
c. 1400, "fickle, not steadfast," from Old French inconstant "variable, eccentric" (14c.), from Latin inconstantem (nominative inconstans) "changeable, fickle, capricious," from in- "not, opposite of, without" (see in- (1)) + constantem (see constant). Related: Inconstantly.
inconstance n.
late 14c., inconstaunce, "changeableness in action, feeling, etc.; fickleness, unsteadiness," from Old French inconstance "inconstancy, instability" (13c.) and directly from Latin inconstantia "inconstancy, fickleness," abstract noun from inconstans "changeable, inconsistent" (see inconstant). In English, inconstancy is now the usual word.