dress down is a verb meaning "censure severely or angrily". It carries 2 recorded senses.
censure severely or angrily
“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”
dress informally and casually
“On Fridays, employees can underdress”
Definitions, synonyms and semantic relations for dress down come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.