Adjective unwell has 2 senses
  1. menstruating, unwell - undergoing menstruation
    Antonym: well (indirect, via ill)
  2. ailing, indisposed, peaked, poorly, sickly, unwell, under the weather - somewhat ill or prone to illness; "my poor ailing grandmother"; "feeling a bit indisposed today"; "you look a little peaked"; "feeling poorly"; "a sickly child"; "is unwell and can't come to work"
    Antonym: well (indirect, via ill)