Synonyms for caulk Found 2 synonyms across 2 meanings for “caulk”. a waterproof filler and sealant that is used in building and repair to make watertight (noun) caulking seal with caulking (verb) calk Explore Related Words Rhymes with caulkSynonyms for caulkingSynonyms for calk Synonym Finder | Rhyme Finder | Poetry Editor