'antiflash' originates from the combining form 'anti-' (ultimately from Greek 'antí', meaning 'against') joined to the English word 'flash' (from Middle English 'flasshen'/'flashen', imitation of a sudden burst).

'antiflash' is a modern compound formed in 20th-century technical and military English by combining 'anti-' + 'flash' to name clothing or equipment intended to protect against flash fires; it did not pass through a distinct older single-word stage but was coined by compounding existing elements.

Initially it literally meant 'against flash' (i.e., resisting a flash); over time it came to refer specifically to protective garments or equipment and their material properties.