1. Impossible to achieve
   - unattainable, undoable, unrealizable, unrealisable [Brit]

See also: impossible, unachievably

• seventy-nine
• seventy-one
• seventy-seven
• seventy-six
• seventy-three
• seventy-two
• sever
• severable
• severable contract
• several
• several-seeded
• severalise
• severalize
• severally
• severalty
• severance
• severance agreement
• severe
• severe acute respiratory syndrome
• severe combined immunodeficiency
• severe combined immunodeficiency disease
• severed
• severely
• severeness
• severing