pinhead

1. (slang) A foolish or stupid person.Examples: "I don't want to be a pinhead no more / I just met a nurse that I could go for"; "My daddy repairs cars driven by women who are pinheads."; "Percy, who hadn't noticed that Fred had bewitched his prefect badge so that it now read "Pinhead," kept asking them all what they were sniggering at."Synonyms: doofus, dumbbell, dunce, addle-brain, addlehead, addle pate, airhead, baboonslang

2. (slang) A telemark skier.slang

3. (slang, medicine) A human head that is unusually tapered or small, often due to microcephaly, or a person with that trait. Often promoted in freak shows as "human pinheads".Examples: "The microcephalic idiot is an unfortunate with a "pinhead," sometimes exhibited as a "what's-it" in circus side-shows, whose mental age never goes beyond that of an imbecile."; "Zip the What-Is-It was simply a Negro idiot. […] For half an hour at a time, David Belasco used to watch Zip at Coney Island. The producer insisted he saw signs of intelligence in the pinhead […]"slang

4. (slang, pet stores) A newborn cricket used as food for pets.Examples: "A newly hatched gecko will need pretty small crickets, but you will not have to go all the way down to pinheads."; "Crickets can be purchased in many sizes from newborns ("pinheads") to adults."slang

5. (mycology) The immature juvenile fruiting body of a mushroom prior to its gills opening.