Off-Color Meaning

(idiomatic) in poor health

Example: Of the wrong color.
1936, Chemical Industries (volume 38, page 400)
  Careful control of mixing at the central point reduces the possibility of off-color paint in some booths, and uniform pressure at the spray guns is easily maintained.
  He told an off-color joke.
  The critics described the pop star's new album as very off-color.
  I feel a bit off-color today.