Meaning

noun a man who is much concerned with his dress and appearance

noun a sailing vessel with two masts; a small mizzen is aft of the rudderpost

adjective very good

originBorrowed from Scots dandy (“a fop; one who is well-dressed”). Of uncertain origin. Possibly from Dandy, a diminutive of Andrew, yet the Scots word is used also in reference to women. Alternatively, possibly a back-formation of Scots dandilly, dandillie (“one who is spoiled or pampered; a "pet"”). Compare English dandle and dander.

Etymology from Wiktionary, CC BY-SA 3.0