1530s, "a cleaning out, removal, clearance," from rid + -ance. The meaning "a deliverance from something superfluous or unwanted" is from 1590s. Good riddance, "a welcome relief from unpleasant company or an embarrassing connection" attested from 1650s. Shakespeare has gentle riddance (1590s); Middleton has fair riddance (1610s).
"characteristic of city life, pertaining to cities or towns," 1610s (but rare before 1830s), from Latin urbanus "of or pertaining to a city or city life; in Rome," also "in city fashion, polished, refined, cultivated, courteous," but also sometimes "witty, facetious, bold, impudent;" as a noun, "city dweller," from urbs (genitive urbis) "city, walled town," a word of unknown origin.
The word gradually emerged in this sense as urbane became restricted to manners and styles of expression. In late 20c. American English gradually acquiring a suggestion of "African-American." Urban renewal, euphemistic for "slum clearance," is attested from 1955, American English. Urban sprawl recorded by 1958. Urban legend attested by 1980.
mid-14c., "doing no evil; free from sin, guilt, or moral wrong," from Old French inocent "harmless; not guilty; pure" (12c.), from Latin innocentem (nominative innocens) "not guilty, blameless; harmless; disinterested," from in- "not" (see in- (1)) + nocentem (nominative nocens), present participle of nocere "to harm," from *nok-s-, suffixed form of PIE root *nek- (1) "death."
Meaning "free from guilt of a specific crime or charge" is from late 14c., as is the meaning "with childlike simplicity or artlessness." Humorous sense "free, devoid of" is from 1706. The noun meaning "person who is innocent of sin or evil, artless or simple person" is from c. 1200, especially a young child (who presumably has not yet sinned actively). The Holy Innocents (early 14c.) were the young children slain by Herod after the birth of Jesus (Matthew ii.16), hence Innocents day (Dec. 28).
Indo-European words for "innocent" are generally negative compound of the word for "guilty." An exception is the Germanic group represented by Gothic swikns (also "pure, chaste"), Old Norse sykn "free from guilt, innocent" (especially as a law term), Old English swicn "clearance from a charge," also "cleansing," but these are of uncertain origin.