什么是 headlong?With the head leading; headfirst: The runner slid headlong into third base. In an impetuous manner; rashly.At breakneck speed or with uncontrolled force.Done with the head leading; headfirst: a headlong dive. Impetuous; rash. See Synonyms at impetuous.Uncontrollably forceful or fast.Archaic Steep; sheer.