handgonne
A handheld pre-matchlock black-powder gun.
historical
mere dry-as-dust knowledge of how Cæsar invaded Gaul, or Hannibal Italy, is about as useful as a knowledge of the "handgonne" would be for working a 12-pounder breech-loader.
Where it comes from
Learned borrowing from Middle English handgonne. Doublet of handgun.
Adapted from the Wiktionary entry handgonne (CC BY-SA 4.0).