Waterproof is a term used to describe materials that are resistant to water. The crossword solutions for this term include SEAL, RAINCOAT, SEALED, IMPERMEABLE, OILSKIN, OILCLOTH, SLICKER, TARPAULIN, and CAULK. SEAL is a 4 letter word that refers to a material used to block the passage of air, gas, or liquid. RAINCOAT is an 8 letter word that describes a waterproof outer garment. SEALED is a 6 letter word that means to close off or make IMPERMEABLE. IMPERMEABLE is an 11 letter word that means not allowing liquids or gases to pass through. OILSKIN is a 7 letter word that is a waterproof fabric made from cotton treated with oil and wax. OILCLOTH is an 8 letter word that is a waterproof fabric treated with oil and pigment. SLICKER is a 7 letter word that is a waterproof coat worn by farmers and fishermen. TARPAULIN is a 9 letter word that is a waterproof sheet of canvas or plastic. CAULK is a 5 letter word that is a waterproof sealant used to fill gaps in structures.