Bulletproof

How to spell bulletproof

11 letters · 3 syllables

How to pronounce bulletproof

Say the part in capitals loudest.

What does bulletproof mean?

1. adjectiveAble to stop or withstand bullets without being penetrated.
2. adjectiveSo well prepared or constructed that it cannot easily fail or be challenged.

Bulletproof in a sentence

• The security detail wore bulletproof vests under their jackets.

• The lawyers spent weeks making the contract bulletproof before signing.

• The bank installed bulletproof glass at every teller window.

• Her alibi was bulletproof, supported by receipts and witnesses.

Where does bulletproof come from?

Language of origin: French

This is a transparent English compound, joining 'bullet' and 'proof', but both halves travelled a long way to meet. 'Bullet' arrived in the 1500s from the French boulette, a diminutive of boule meaning 'ball', which itself descends from the Latin bulla, a word that originally meant a rounded knob, bubble, or stud. 'Proof' comes through Old French preuve from the Latin probare, 'to test or prove', and in compounds like this it carries the older sense of 'tested against and able to resist', the same sense seen in 'waterproof' and 'fireproof'. The combined word 'bulletproof' is recorded from the seventeenth century, first describing armour and plate that had literally been test-fired to show it could stop a shot. The figurative meaning, something so well prepared that it cannot fail or be challenged, grew up much later. Because both parts are familiar everyday words, the only spelling trap is remembering it is written solid as one word with a double 'l' in 'bullet'.

How the word is built

• bullet (small projectile)
• proof (able to resist or withstand)