What is the meaning of dressing down?

noun

• A severe scolding.
  • synonyms: castigation, earful, bawling out, chewing out, upbraiding, going-over

verb

• Censure severely or angrily.
  • usage: "The mother scolded the child for entering a stranger's car"; "The deputy ragged the Prime Minister"; "The customer dressed down the waiter for bringing cold soup"
  • synonyms: call on the carpet, take to task, rebuke, rag, trounce, reproof, lecture, reprimand, jaw, dress down, call down, scold, chide, berate, bawl out, remonstrate, chew out, chew up, have words, lambaste, lambast
• Dress informally and casually.
  • usage: "On Fridays, employees can underdress"
  • synonyms: dress down, underdress