The Spanish verb 'erizar' (to bristle or to make hair stand on end) comes from the Spanish noun 'erizo' (hedgehog) combined with the verbal suffix '-ar'. The noun 'erizo' itself derives from the Latin word 'ericius', which also meant 'hedgehog'. This etymology makes intuitive sense since hedgehogs are known for their distinctive ability to raise their spines when threatened, which is exactly the kind of bristling action that 'erizar' describes.

The most directly related Spanish word is 'erizo' (hedgehog), which is simpler and more common than the verb 'erizar'. While 'erizo' refers specifically to the spiny mammal, the derived verb 'erizar' generalizes the hedgehog's defensive behavior to describe any situation where hair, fur, or similar structures stand on end.

While there isn't a direct English cognate from the same Latin root 'ericius', English speakers might find it helpful to know that the scientific name for hedgehog genus, 'Erinaceus', comes from the same Latin root. The connection between 'erizar' and this scientific term helps reinforce the link to the hedgehog's characteristic bristling behavior.