'snag' originates from Scandinavian, specifically Old Norse 'snagi', where the root meant 'a projecting point, jutting piece'.

'snagi' (Old Norse) passed into English circulation as a word for a projecting point or obstruction and developed into the modern English 'snag'. The verb sense ('to catch' or 'to tear on a projection') emerged later in Early Modern English.

Initially, it meant 'a projecting point or jutting piece', but over time it evolved to include 'an obstacle or hitch' and the verb sense 'to catch or entangle on a projection' and colloquially 'to obtain quickly'.