unworkable (adj.)

• impracticable
• impractical
• inapplicable
• infeasible
• inoperable
• inoperative
• insuperable
• insurmountable
• nonfunctional
• otiose
• unachievable
• unattainable
• undoable
• unemployable
• unfeasible
• unfit
• unhelpful
• unrealizable
• unserviceable
• unsuitable
• unsurmountable
• unusable
• useless