"in the process of becoming dead, decaying from life," mid-15c., present-participle adjective from die (v.).
1650s, "to go or retire into the country, live a country life," from Latin rusticatus, past participle of rusticarti "to live in the country," from rusticus (see rustic). In English university slang 18c.-19c., transitive, "to suspend (a student) from studies for a time and send away as punishment." Related: Rusticated; rusticating.
1726, in on the qui vive "on the alert," from French être sur le qui vive "be on the alert," from the phrase qui voulez-vous qui vive? sentinel's challenge, "whom do you wish to live?" In other words "(long) live who?" meaning "whose side are you on?" (The answer might be Vive la France, Vive le roi, etc.). From qui (from Latin qui "who") + vive, third person singular present subjunctive of vivre, from Latin vivere "to live" (see viva).