ad·um·brate / ˈadəmˌbrāt; əˈdəm-/ • v. [tr.] formal report or represent in outline: James Madison adumbrated the necessity that the Senate be somewhat insulated from public passions. ∎  indicate faintly: the walls were not more than adumbrated by the meager light. ∎  foreshadow or symbolize. ∎  overshadow or obscure.DERIVATIVES: ad·um·bra·tion / ˌadəmˈbrāshən/ n.ad·um·bra·tive / əˈdəmbrətiv; ˈadəmˌbrā-/ adj.

adumbrate shadow forth, prefigure XVI; over-shadow XVII. f. pp. stem of L. adumbrāre, f. AD- + umbra shade, shadow; see -ATE3.
So adumbration XVI (earlier than the vb.). — L.