The Collaborative International Dictionary of English v.0.48:
ladder-proof \ladder-proof\ adj. resistant to runs or (in Britain) ladders; -- of hosiery. Syn: runproof, run-resistant. [WordNet 1.5 +PJC]WordNet (r) 3.0 (2006):
ladder-proof adj 1: (of hosiery) resistant to runs or (in Britain) ladders [syn: runproof, ladder-proof, run-resistant]