bulletproof

adjective

bul·​let·​proof ˈbu̇-lət-ˌprüf 

also ˈbə-

1

: impenetrable to bullets

bulletproof glass

2

: not subject to correction, alteration, or modification

a bulletproof argument

3

: invincible

Synonyms of bulletproof

• invincible
• armored
• invulnerable
• impregnable
• unbeatable
• unstoppable
• insurmountable
• indomitable
• unconquerable

Examples of bulletproof in a Sentence

The car has bulletproof windows.

The police officer was wearing a bulletproof vest.

Recent Examples on the Web

Yet Rubio remains powerful and relatively aloof, not bulletproof but at least wearing a little bit of Teflon. —Ross Douthat, Mercury News, 26 Dec. 2025

With this approach, some of our leaders learn to be bulletproof and irreplaceable. —Rolling Stone Culture Council, Rolling Stone, 23 Dec. 2025

Safra’s Monaco residence had state-of-the-art security as well as bulletproof glass and steel shutters on every window, according to Dateline. —Alex Gurley, PEOPLE, 21 Dec. 2025

Some of the gunfire was captured on video that shows the spray of bulletproof glass as shots hit the 3-inch-thick windshield of an armored vehicle. —Tony Aiello, CBS News, 4 Dec. 2025

Word History

First Known Use

1693, in the meaning defined at sense 1

Rhymes for bulletproof

• fireproof
• waterproof
• weatherproof
• aloof
• behoof
• disproof
• flameproof
• foolproof
• greaseproof
• leakproof
• reproof
• soundproof

Kids Definition

bulletproof

adjective

bul·​let·​proof ˈbül-ət-ˌprüf 

: so made as to prevent the passing through of bullets

bulletproof glass