“缄口不言”用英文怎么写？

1.close-mouthed,这是个形容词，表示not willing to say much about sth because you want to keep a secret “守口如瓶；缄口不言”2.keep mum,这里mum是个形容词，不是“妈妈”的意思，而是表示to say nothing about sth; to stay quiet?He kept mum about what he'd seen. 他对他所看到的只字不说。3. keep silent/quiet