: firmly determined The mayor was dead set against [=strongly opposed to] the plan. She was dead set on [=completely certain about] going to college.

Where did the phrase dead set come from?

This deadset Australianism dates back to the 1890s. There has been a lot of discussion about the origin of this term, and many fabled origins have been put forward, generally having something to do with soldiers from army barracks supporting a certain team at a certain place.

What does Dead Set Legends mean?

a serious or determined attempt; firm effort: He made a dead set at winning the championship.