Webster’s Revised Unabridged Dictionary · 1913
Headlong
Head′long′ (-lŏng′; 115), adv. [OE. hedling, hevedlynge; prob. confused with E. long, a. & adv.]
1. With the head foremost; as, to fall headlong. Acts i. 18.
2. Rashly; precipitately; without deliberation.
3. Hastily; without delay or respite.
Head′long, a. 1. Rash; precipitate; as, headlong folly.
2. Steep; precipitous. [Poetic]
Like a tower upon a headlong rock. Byron.