1. Open to doubt or suspicion
   - doubtful, dubious, dubitable, doubtable

See also: questionable

• black bead
• black bean
• black bear
• black bearberry
• black bee
• black beech
• black belt
• black bile
• black bindweed
• black birch
• black book
• black box
• black bread
• black bream
• black bryony
• black buffalo
• black calla
• black caraway
• black carpet beetle
• black cat
• black catechu
• black cherry
• black cherry tree
• black cohosh
• black comedy