dandy (n.) Look up dandy at Dictionary.com
c.1780, of uncertain origin, first appeared in a Scottish border ballad:
I've heard my granny crack
O' sixty twa years back
When there were sic a stock of Dandies O
etc. In that region, Dandy is dim. of Andrew. In vogue in London c.1813-19. His fem. counterpart was a dandizette (1821) with Fr.-type ending. The adjective dandy first recorded 1792; very popular c.1880-1900.