Blow-up is a term used to describe an explosion or a sudden burst of something, such as a tire or a balloon. Synonyms for blow-up include detonation, eruption, burst, blast, and explosion. These words can be used to describe a sudden and dramatic change in a situation or an intense emotional outburst. Other synonyms for blow-up include combustion, flash, and flare-up, which are often used in the context of a fire or a sudden burst of anger. Ultimately, the choice of synonym depends on the context and the intended meaning of the phrase, but all of these words have the power to convey a sudden and explosive event.