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

• 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

From bulletproof glass to panic buttons, jurisdictions across the U.S. are taking unprecedented steps to protect election workers and ballots amid concerns about voter intimidation, fraud and even violence at the polls. —Sophia Cai, Axios, 20 Sep. 2024

The feds alleged that the pair procured over $1 million worth of luxury items — including a bulletproof Escalade, a giant TV, and expensive watches — without ever paying for them. —Jon Blistein, Rolling Stone, 15 Apr. 2025

Gmail versus the rest Statista But Gmail (and other) security restrictions are not bulletproof — far from it. —Zak Doffman, Forbes.com, 30 Mar. 2025

All that said, there are no platforms that are bulletproof for sharing secrets. —Zak Doffman, Forbes, 25 Mar. 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