If a person, an animal, or a machine is balky, it will not do what you need it to do. A balky horse stops and will not go. A balky old car coughs and refuses to start. A balky child digs in and will not move. The feeling is “I should be able to make this work, and it will not.” It is a bit informal, and you hear it more in American English (the related verb is often written baulk in British English). You also hear balk at — to refuse because something feels too much — and balky is that same stubborn stop, turned into a describing word. Though actually, it is not the same as broken: a balky thing might work perfectly the next minute. It just will not, right now.

不聽話的、動不動就卡住不肯動的（人、動物、機器都能用）