The term 'STOP UP' can be defined by a variety of words, including PLUG (4 letters), OBSTRUCT (8 letters), CLOG (4 letters), CORK (4 letters), CONGEST (7 letters), TAMP (4 letters), SEAL (4 letters), DAM (3 letters), STEM (4 letters), and OCCLUDE (7 letters). These words all refer to the act of blocking or preventing the flow of something, such as air, water, or other substances. For example, PLUG and CORK are often used to refer to the act of blocking a hole with an object, while OBSTRUCT and CONGEST refer to the act of blocking a passage with an object or material. Similarly, TAMP, SEAL, DAM, STEM, and OCCLUDE all refer to the act of blocking or preventing the flow of something.