(bound form) the ghost of someone eaten by a tiger who then assists the tiger in killing others, as mentioned in the idiom 为虎作伥 wèi​hǔ​zuò​chāng

(literary) a person who acts wildly, recklessly, or without knowing what they are doing

(bound form) groping or at a loss, as in the reduplicated form 伥伥 chāng​chāng