Galoot's origins are unknown. The first known use of the term -- referring to a big, stupid, awkward man -- goes back to 1866. The
Dutch term
gelubt, which means
eunuch, might be the
progenitor. It's possible the term had its origin in the US navy, such as it was in 1866. Many navy ships carried a compliment of soldiers. However the soldiers, not being able seamen, contributed little to a ship's operation. They got to sit around, waiting to repel
Spaniards or
Huguenots or whatever.
This obvious lack of effort earned them the snarling disrespect of the actual sailors, who would refer to them as "galoots" behind their back. This
dovetails nicely with the Dutch eunuch origin as soldiers aboard ship do seem very eunuch like.