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

See also: questionable

• Pennsylvanian
• Pennsylvanian period
• penny
• penny ante
• penny ante poker
• penny arcade
• penny bank
• penny dreadful
• penny for your thoughts
• penny grass
• penny pincher
• penny stock
• penny-farthing
• penny-pinch
• penny-pinching
• penny-wise
• pennycress
• pennyroyal
• pennyroyal oil
• pennyweight
• pennywhistle
• pennywort
• pennyworth
• Penobscot
• Penobscot Bay