英语词源字典 - 在线词源网站

disconcert (v.)[disconcert 词源字典]: 1680s, from Middle French disconcerter (Modern French déconcerter) "confused," from dis- "do the opposite of" (see dis-) + concerter (see concert). Related: Disconcerted; disconcerting; disconcertingly.[disconcert etymology, disconcert origin, 英语词源]
sedition (n.): mid-14c., "rebellion, uprising, revolt, concerted attempt to overthrow civil authority; violent strife between factions, civil or religious disorder, riot; rebelliousness against authority," from Old French sedicion (14c., Modern French sédition) and directly from Latin seditionem (nominative seditio) "civil disorder, dissention, strife; rebellion, mutiny," literally "a going apart, separation," from se- "apart" (see secret) + itio "a going," from past participle of ire "to go" (see ion).

Meaning "conduct or language inciting to rebellion against a lawful government" is from 1838. An Old English word for it was folcslite. Less serious than treason, as wanting an overt act, "But it is not essential to the offense of sedition that it threaten the very existence of the state or its authority in its entire extent" [Century Dictionary].