穿孔 means 'to make a hole (by drilling, punching, or through natural decay)'. It is a separable verb (离合词): the noun 孔 can split off from 穿 when you add a measure word, adjective, or other modifier — for example, 穿了一个孔 ('made a hole'). In everyday use, you'll hear it for drilling holes in walls or metal, for medical perforations, and for office tasks like punching holes in paper. The word stays together when followed by an object or in fixed medical terms like 胃穿孔 ('gastric perforation').