The term 'GUM UP' is an informal phrase that means to cause something to become stuck, tangled, or otherwise not working properly. The crossword solutions for this term are CLOG (4 letters), BOTCH (5 letters), SNARL (5 letters), and MESSUP (6 letters). All of these words have similar meanings, with CLOG referring to a blockage, BOTCH meaning to do something poorly, SNARL referring to a tangle, and MESSUP meaning to make a mistake. Together, these words all describe the same concept of gumming up something and making it not work properly.