What is the meaning of dandy?

noun

• A man who is much concerned with his dress and appearance.
  • synonyms: dude, fop, gallant, sheik, beau, swell, fashion plate, clotheshorse
• A sailing vessel with two masts; a small mizzen is aft of the rudderpost.
  • synonyms: yawl

adjective

• Very good.
  • usage: "he did a bully job"; "a neat sports car"; "had a great time at the party"; "you look simply smashing"
  • synonyms: bang-up, bully, corking, cracking, great, groovy, keen, neat, nifty, not bad, peachy, slap-up, swell, smashing