From hollow + earth + -er.
hollow earther (plural hollow earthers)
- Someone who believes the Earth is hollow.
- 2001, F. Gwynplaine MacIntyre, Macintyre's Improbable Bestiary, Wildside Press, 24.
- Beware the Hollow-Earther! Beware the troglodytes / They make their homes in catacombs, and prowl on moonless nights . . .