bomb-proof adj.

"explosive projectile," originally consisting of a hollow ball or shell filled with explosive material, 1580s, from French bombe, from Italian bomba, probably from Latin bombus "a deep, hollow noise; a buzzing or booming sound," from Greek bombos "deep and hollow sound," echoic. Thus probably so called for the sound it makes.

Originally of mortar shells, etc.; modern sense of "explosive device placed by hand or dropped from airplane" is from 1909. The meaning "old car" is from 1953. The meaning "success" is from 1954 (late 1990s slang the bomb "the best" probably is a fresh formation); opposite sense of "a failure" is from 1961. The bomb "the atomic bomb" is from 1945. Compare shell (n.).

c. 1200, preove "evidence and argumentation to establish the fact of (something) beyond reasonable doubt," from Anglo-French prove, preove, Old French proeve, prueve "proof, test, experience" (13c., Modern French preuve), from Late Latin proba "a proof," a back-formation from Latin probare "to prove" (see prove). "The devocalization of v to f ensued upon the loss of final e; cf. the relation of v and f in believe, belief, relieve, relief, behove, behoof, etc." [OED].

The meaning "act of proving" is early 14c. The meaning "act of testing or making trial of anything" is from late 14c., from influence of prove. Meaning "standard of strength of distilled liquor" is from 1705, on the notion of "having been tested as to degree of strength." The use in photography is from 1855. The typographical sense of "trial impression to test type" is from c. 1600. The numismatic sense of "coin struck to test a die" is from 1762; now mostly in reference to coins struck from highly polished dies, mainly for collectors.

The adjectival sense "impenetrable, able to resist" (as in proof against) is recorded from 1590s, from the noun in expressions such as proof of (mid-15c.), hence extended senses involving "of tested power against" in compounds such as fireproof (1630s), rust-proof (1690s), waterproof (1725), fool-proof (1902), etc. Shakespeare has shame-proof. Expression the proof is in the pudding (1915) is a curious perversion of earlier proof of the pudding shall be in the eating (1708), with proof in the sense "quality of proving good or turning out well" (17c.).