adj

• (often derogatory) Fine-looking; only superficially attractive; initially appealing but having little substance; see petty.
  "Damned by the Socialists as "traitors to the working class," its leaders were decried by Tories as "faceless peddlers of politics with a pretty little trinket for every taste.""
• (UK, sometimes derogatory) Effeminate.
• (dated) Moderately large; considerable.
  "they flung all the goods in the house out at the windows into the street, or into the sea, as they supposed; thus they continued mad a pretty season […]."
• (dated) Excellent, commendable, pleasing; fitting or proper (of actions, thoughts etc.).
  "Some people are surprised, I believe, that that the eldest was not [named after his father], but Isabella would have him named Henry, which I thought very pretty of her."

adv

• (dialect) Prettily, in a pretty manner.
  "'The boy sings pretty, don't he, Master Marner?'"