Word Study
lightproof
OXFORD DICTIONARY
lightproof, adj. able to resist the harmful effects of (esp. excessive) light.
THESAURUS
lightproof
airtight, close, compact, dustproof, dusttight, fast, firm, gasproof, gastight, hermetic, hermetically sealed, lighttight, oilproof, oiltight, rainproof, raintight, sealed, shut fast, smokeproof, smoketight, snug, staunch, stormproof, stormtight, tight, water-repellant, waterproof, watertight, windproof, windtightFor further exploring for "lightproof" in Webster Dictionary Online