This is a defensive bid, usually showing a weak two-suited hand. A cuebid of opponent's major suit shows the other major, plus a minor. A minor-suit cuebid shows both majors.
S: KJxx H: x D: xxxx C: xxxx S: AQxxx H: KJxxx D: xx C: x W N E S 1C 2C X 4S X P/O
source: bbuff@user.rose.com