The term 'BLOCKS UP' can be solved by three different crossword solutions: CLOGS (5 letters), DAMS (4 letters), and OBSTRUCTS (9 letters). CLOGS are a type of blockage caused by an accumulation of material, such as dirt, debris, or other substances. DAMS are structures built across rivers to control the flow of water, often for the purpose of creating reservoirs. OBSTRUCTS is a verb meaning to prevent or hinder the passage of something, such as a person or vehicle. All three terms refer to the act of blocking or impeding the flow of something.