Related Clues:

• Thing that oughtn't be done
• Frowned-upon action
• From underside, cored shallot? That's forbidden ...
• Eating candy before dinner, e.g
• 'That's a ___' ('You can't do that')
• Thing you mustn't do
• Two words a toddler hears often
• You shouldn't do this
• Taboo behavior
• This is impossible without oxygen
• Prohibited action (2 words)
• Giving chocolate to the dog, e.g
• Section of Matterhorn on own? Impossible
• Running by the pool, e.g
• Joking about tragedies, e.g