Used other than figuratively or idiomatically: see off, top, head. / (idiomatic) In an extemporaneous manner; without careful thought, preparation, or investigation.

present participle of head-butt

(idiomatic) To identify something exactly; to arrive at exactly the right answer.

(informal) The person in charge; the highest-ranking person in an organization.

The hub of a propeller / The central part of a propeller, into which the blades fit

A screwdriver with a '+' shaped head for turning screws so socketed. / A screw turned by such a screwdriver.

(idiomatic) Direct, abrupt, blunt or unequivocal; not prevaricating. / Of a collision, from the front or in the direction of motion.

With the front of a vehicle. / With direct confrontation.

A collision from the front.

(idiomatic) To act in a haphazard or aimless way; to act frantically or without control.