1. stupid, thick-headed ...Bk1830 Eng. dial.
2. thatched with straw or stubble ...Bk1830 Eng. dial.
of unknown origin;
from A General Dictionary of Provincialisms, by William Holloway, 1888: "possibly from culfre, Sax. a pigeon - that is pigeon-headed, pigeons not being particular remarkable for sagacity"
FIRST DOCUMENTED USE
1830 - CULVER-HEADED. adj. In common acceptation it seems to mean thick-headed, stupid. But this must be an improper use. It should rather mean soft-headed, harmless "an it were any sucking dove!" The difference might be little or nothing in point of stupidity.
From: The Vocabulary of East Anglia
- Robert Forby