Jaywalking is a portmanteau of jay and walking. Jay (archaic colloquial) itself means:
Applied to humans in sense of "impertinent chatterer, flashy dresser" from 1620s. […] Jay was slang for "fourth-rate, worthless" (1888) e.g. a jay town.
a fourth-rate, worthless walker.
(inspired by the jay bicyclists we almost mowed down this morning. source: Online Etymology Dictionary)
