tamperproof

or tam·per-proof

[tam-per-proof]

Origin of tamperproof

First recorded in 1885–90; tamper1 + -proof
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Word Origin and History for tamperproof
adj.

also tamper-proof, 1886, from tamper (v.) + proof.

Online Etymology Dictionary, © 2010 Douglas Harper