'seditious' originates from Latin, specifically the adjective 'seditiosus' (from the noun 'seditio' meaning 'insurrection' or 'dissension'), via Anglo-French/Middle English.

'seditious' changed from Middle English/Anglo-French forms (e.g. Middle English 'seditious', Anglo-French 'seditieux') and eventually became the modern English word 'seditious'.

Initially, it referred directly to actions or tendencies toward 'insurrection' or open dissent; over time it has come to describe speech, writing, or behavior that incites or promotes discontent or rebellion against authority.