mid-14c., declaren, "explain, interpret, make clear;" late 14c., "make known by words, state explicitly, proclaim, announce," from Old French declarer "explain, elucidate," or directly from Latin declarare "make clear, reveal, disclose, announce," from de-, here probably an intensive prefix (see de-) + clarare "to clarify," from clarus "clear" (see clear (adj.)).
From mid-15c. as "assert, affirm." Intransitive sense "make known one's thoughts or intentions" is by 1840. Related: Declared; declaring.
