bubble head
n.— «Since I’ve never talked to a bubble head, or had much knowledge (post WWII) on submarine operations I really can’t comment from that side of the coin. However, being on an ASW platform in the past, I can comment from that side.» —“Re: Are Aircraft Carriers Obsolete?” Usenet: sci.military Jan. 24, 1989. (source: Double-Tongued Dictionary)
Further reading
In Scotland and Northern England, something that’s kenspeckle is “conspicuous.” This word likely comes from Scandinavian languages and is related to English ken, meaning “range of knowledge.” And it’s not just ken...
When you had sleepovers as a child, what did you call the makeshift beds you made on the floor? In some places, you call those bedclothes and blankets a pallet. This word comes from an old term for “straw.” And: What’s the story...