Un-forbearing is a relatively uncommon word, which means to not exercise restraint or patience. It is typically used to describe someone who is easily provoked or disturbed and is unable to control their emotions or reactions. There are several synonyms that convey similar meanings, including impulsive, rash, hasty, uncontrolled, unrestrained, and impatient. Each of these words suggests an inability to wait or delay gratification and a tendency to act impulsively or without considering the consequences. Other possible synonyms for un-forbearing include intolerant, irritable, testy, and short-tempered, all of which denote a lack of patience or forbearance. Ultimately, the choice of synonym will depend on the context and the writer's intended meaning.