spartan

This word comes from the ancient Spartans, who were famous for their discipline, simplicity, and toughness. Something described this way is being compared to them by analogy.

The word's use has stayed close to its origin: it's still invoked whenever someone wants to evoke that same austere, no-frills toughness the Spartans were known for.

The facts given don't support a cognate connection, so none is claimed here.