c.1200, "continue, persevere," from Anglo-French suer "follow after, continue," Old French suir, sivre "pursue, follow after, sue in court" (Modern French suivre), from Vulgar Latin *sequere "follow," from Latin sequi "follow" (see sequel). Sense of "start a lawsuit against" first recorded c.1300, on notion of "following up" a matter in court. Sometimes short for ensue or pursue. Meaning "make entreaty, petition, plead" (usually with for) is from late 14c. Related: Sued; suing.