Someone who or something that pecks, striking or piercing in the manner of a bird's beak or bill, particularly:

(by extension of the sense ‘beak’) A nose.

(by extension, from the expression ‘keep one's pecker up’) Spirits, nerve, courage.

A dickhead: an unpleasant, stupid or mean person.

“I dunno what this peckerhead thinks he's doin' but he's about to fall off that bridge.”

An electric motor's terminal connection or wiring box.