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 perhaps 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.
It forms all or part of: acclaim; acclamation; Aufklarung; calendar; chiaroscuro; claim; Claire; clairvoyance; clairvoyant; clamor; Clara; claret; clarify; clarinet; clarion; clarity; class; clear; cledonism; conciliate; conciliation; council; declaim; declare; disclaim; ecclesiastic; eclair; exclaim; glair; hale (v.); halyard; intercalate; haul; keelhaul; low (v.); nomenclature; paraclete; proclaim; reclaim; reconcile.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit usakala "cock," literally "dawn-calling;" Latin calare "to announce solemnly, call out," clamare "to cry out, shout, proclaim;" Middle Irish cailech "cock;" Greek kalein "to call," kelados "noise," kledon "report, fame;" Old High German halan "to call;" Old English hlowan "to low, make a noise like a cow;" Lithuanian kalba "language."
Old English utlagian "to banish, proscribe, declare an outlaw; to deprive (someone) of the benefits and protections of the law," from utlaga "an outlaw" (see outlaw (n.)). Related: Outlawed; outlawing.
mid-15c., protesten, "to declare or state formally or solemnly, bear witness or testimony to," from Old French protester and directly from Latin protestari "declare publicly, testify, protest" (see protest (n.)). Original sense preserved in to protest one's innocence. The meaning "make a solemn or formal declaration (often in writing) in condemnation of an act or measure, proposed or accomplished," is from c. 1600. The word's association with marches and rallies arose in 20c. Related: Protested; protesting.
1660s, "declare guilty of a crime;" 1670s, "censure, hold up to blame," from Latin criminatus, past participle of criminare "to accuse of a crime," from crimen (genitive criminis) "crime" (see crime). Related: Crimination (1580s).