word-forming element from proof (adj.) "impenetrable, able to resist" (as in proof against), which is recorded from 1590s, extended from proof (n.) in expressions such as proof of (mid-15c.).
Hence the extended senses involving "of tested power against" in compounds such as storm-proof (1590s), fireproof (1630s), rust-proof (1690s), bomb-proof (1702), waterproof (1725), fool-proof (1902), Milton's branching elm star-proof. A Donne sermon from 1631 has temptation-proof.
In later use often in advertisers' coinages, such as spill-proof, attested from 1909 in reference to carpet sweepers, by 1920 also in newspaper ads for garbage cans, clothes for boys, a dairy pail a cow can't kick over, etc. (It was used by 1902 of a wagon that won't upset.) Kiss-proof is touted as a quality of lipsticks by 1924, earliest of face-powder (1906); in 1890s it was an occasional whimsical word (as in kiss-proof mask, a gift for one suddenly popular). Also child-proof (1933). Shakespeare has shame-proof.