Clag is a sticky, thick substance. Synonyms for clag include glue, paste, gum, adhesive, bond, and cement. These words all describe materials that can be used to stick objects together. Some other words that can be used as synonyms for clag are tack, stickiness, and thickness. These words describe the properties of clag and are useful when trying to describe its texture or consistency. Overall, there are many different words that can be used as synonyms for clag, and they all help to convey the same idea of a substance that is sticky and thick.