lighttight

light +‎ tight; compare watertight.

lighttight (comparative more lighttight, superlative most lighttight)

1. Having no crack or aperture where light can enter.
   • 2000, Stephen G. Anchell, The darkroom cookbook (page 127)

     From a practical point of view it is not always possible to achieve an absolute lighttight home darkroom.

• light-tight
• light tight

• airtight, air-tight
• coldtight, cold-tight
• drafttight, draft-tight
• draughttight, draught-tight
• driptight, drip-tight
• dusttight, dust-tight
• gastight, gas-tight
• heattight, heat-tight
• jointtight, joint-tight
• leaktight, leak-tight
• liquidtight, liquid-tight
• oiltight, oil-tight
• pressuretight, pressure-tight
• raintight, rain-tight
• sandtight, sand-tight
• soiltight, soil-tight
• watertight, water-tight
• weathertight, weather-tight