\Half"cock`\, v. t. [imp. & p. p. {Halfcocked}; p. pr.
& vb. n. {Halfcocking}.]
To set the cock of (a firearm) at the first notch.
{To go off halfcocked}.
(a) To be discharged prematurely, or with the trigger at half
    cock; -- said of a firearm.
(b) To do or say something without due thought or care.
    [Colloq. or Low]