Chinaman is a term that is referred to a lefthander's leg spin delivery. In other words, Chinaman is a delivery of a lefthander bowling with a leg spinner's action.
A lefthander's leg spinning delivery or a Chinaman will spin in the opposite direction to that of a normal leg spin. A Chinaman is more akin to an off-break. That is, after pitching it spins towards the leg side (in the case of a right handed batsman). The lefthander's Googly or wrong one, on the other hand, will spin towards the off side after pitching (in case of a right hand batsman).
Paul Adams of South Africa is one of the contemporary bowlers who bowls the Chinaman.