The term 'run up' can be defined as to INCUR, AMASS, INCREASE, or atab something, all of which can be represented by the following crossword solutions: INCUR (5 letters), AMASS (5 letters), INCREASE (8 letters), ATAB (4 letters), and SEWN (4 letters). INCUR means to become liable for something, such as a debt or an expense. AMASS means to accumulate or gather something, such as wealth or possessions. INCREASE means to make something larger or greater in number, size, or amount. Atab is an archaic word meaning to run up or climb. Finally, sewn means to fasten or attach something with stitches.