The etymology of the word navaja is derived from the Latin novacula, meaning razor, and the Andalusian knife known as the navaja is thought to have derived from the navaja de afeitar, or straight razor used for shaving.
Like the straight razor, the navaja's blade folds into the handle when not in use.
that was reinforced with a steel or brass liner, although examples can also be found with expensive materials such inlaid silver, ivory, and even gold.
Its association with barateros, pícaros, jácaros and rufos (gamblers, rogues, ruffians, and thugs) comes from its frequent use as a weapon of the underworld, where it was often used to enforce the collection of gambling debts or to rob innocent victims.
The name was a reference to the oils or unguents applied to the dying as part of the Catholic last sacrament, as it was believed that a man encountering such a knife in a violent confrontation would invariably require administration of the last rites.
With its locking blade, the navaja de muelles was now a versatile fighting knife, able to safely deliver thrusts as well as slashes (cuts).
The navaja de muelles proved sufficiently formidable as an offensive arm that it was specifically named by the Marqués de la Mina, the Spanish military governor of Catalonia, in his edict of prohibiting the carrying of armas blancas, or edged weapons.
A popular slang term for the navaja in the 19th century was herramienta, which translates as "(iron) tool".
the earliest Spanish knives recognizable as navajas date from around the late 1600s.
Many examples of this period were fitted with metal bolsters and butt caps for additional strength and protection; these are often carved, filed, or engraved with decorations.
The typical navaja manufactured today blends traditional styling with modern materials.
One of the more common early varieties of this type of knife was the navaja cortaplumas, used by clerical workers, draftsmen, and notaries to sharpen ink quill tips.