verb

• (reflexive, now rare) To remove one's clothing.
  "She undressed herself before putting on her bedclothes."
• (intransitive) To remove one’s clothing.
  "The doctor asked me to undress for the examination."
• (transitive) To remove the clothing of (someone).
  "Mary began to undress her daughter in preparation for bathtime."
• (transitive, figuratively) To strip something off.

noun

• (now archaic or historical) Partial or informal dress for women, as worn in the home rather than in public.
  "Here he had not waited above ten minutes, when Emilia entered in a most inchanting undress, with all the graces of nature playing about her person, and in a moment rivetted the chains of his slavery beyond the power of accident to unbind."
• (now archaic or historical) Informal clothing for men, as opposed to formal or ceremonial wear.
  "His undress, and the agitation he was apparently in, which she imputed to the effect of her charms, combined to make him appear more interesting both to the mother and daughter […]."