If someone is biddable, they do what they are told and they do not push back. You might hear it about a child, a dog, or — more coldly — about an adult who never argues with the person in charge. It is not a high-frequency everyday word; it can sound slightly old-fashioned, or like a word from training and manners. It is not always a compliment. A biddable person can sound too easy to steer, as if they had no will of their own. The bid inside it is the old verb 'tell someone to do something' (as in 'do as you are bid'), not the auction bid where you offer money. Though actually those two bids later shared a spelling; here you want the 'command' one.

聽話的、乖順的