1. Not penetrable by light
   - lightproof

See also: opaque

• businessman
• businessmen
• businesspeople
• businessperson
• businesswoman
• busk
• busker
• buskin
• busload
• busman
• busman's holiday
• BuSpar
• buspirone
• buss
• bust
• bust a gut
• bust-up
• bust-up takeover
• bustard
• bustard quail
• busted
• bustee
• buster
• Buster Keaton
• bustier