Related Clues:
- One can't access this number more than once
- Unacceptable thing
- Something not acceptaable
- Movement for one knight in time becomes tabu
- Child's taboo
- Jaywalking, e.g
- Something bad
- Slangy veto
- Non-starter (colloq.)
- Colloquial word for an impossibility or non-starter
- Failure (colloq.)
- Deoxygenated failure?
- Doctor, doctor -- I'm a failure!
- Luigi --, Italian avant-garde composer of classical music (1924-90)
- Jumping a line, e.g