1. Without concealment or deception; honest
   "their business was open and aboveboard"
   - straightforward

1. In an honest manner
   "was known for dealing aboveboard in everything"
   - honestly

See also: square, straight

• family Cladoniaceae
• family Clathraceae
• family Clavariaceae
• family Cleridae
• family Clethraceae
• family Clinidae
• family Clupeidae
• family Clusiaceae
• family Cobitidae
• family Coccidae
• family Coccinellidae
• family Coerebidae
• family Colchicaceae
• family Colubridae
• family Columbidae
• family Comatulidae
• family Combretaceae
• family Commelinaceae
• family Compositae
• family Congridae
• family Connaraceae
• family Convallariaceae
• family Convolvulaceae
• family Coprinaceae
• family Coraciidae