noun

• (obsolete) A servant or attendant.
  "The varlet, or follower of the merchant, who was still a youth, though his vigorous frame and embrowned cheek denoted equally severe exercise and rude exposure, started and reddened at this free inquiry, which was enforced by a hand slapped familiarly on his knee, and such a squeeze of the leg as denoted the freedom of the camp."
• (historical) Specifically, a youth acting as a knight's attendant at the beginning of his training for knighthood.
  "[T]here was a little, sleek, fat clerk of the name of Chaucer, who was so apt at rondel, sirvente, or tonson, that no man dare give back a foot from the walls, lest he find it all set down in his rhymes and sung by every underling and varlet in the camp."
• (archaic) A rogue or scoundrel.
  "[W]hen the worlde is fraughted with ſo manye varlettes, that it will be a long time ere a man ſhall diſcerne the faythful from the Hipocrites."
• (obsolete, card games) The jack.