noun · person sent out to gather intelligence, scout information, or act as a detective

将军派出一名探子去查明敌军的动向。

noun · long and narrow utensil used for probing and taking samples from containers

质检员用探子从粮袋里取样。

noun · medical instrument used for exploring body cavities or channels

医生小心地将探子插入伤口以检查深度。