Possible Clues:

• Unworkable
• Not sensible
• Unrealistic
• Unworkable, fanciful
• “The law which attempts a man’s life is ____, unjust, inadmissible” (Marquis de Sade, on capital punishment)
• I can make stuff that doesn't work
• Overlooking the very last pair, Nutmeg's almost useless
• Not suitable for use
• Q: Are you an idealist? A: No. ___
• One mark on science exam? That's not much use