dead set noun 4adjective 2forms 4 noun4 •The rigid pose a hunting dog assumes when pointing out game to a hunter.The judge at the dog show took points off the Irish setter's dead set because its right ear twitched a few times. •A pointed and persistent attack on a person. •(figurative) A determined effort.I might not graduate first in my class, but I'll make a dead set at it. •A fixed or stationary condition arising from obstacle or hindrance; a deadlock. adjective2 •Unswervingly dedicated; resolutely determined.If John is dead set on marrying Catherine, his parents' objection will only provoke a falling out.The governor is dead set against the concealed weapons permit legislation and will veto it even if it costs her the re-election. •(Australia, informal) Complete and utter; total.He is a dead set fool. formsdead sets · dead-sets · more dead set · most dead set