Fudge, e.g., to a dieter

• Social blunder for Nanette?
• Nail-biting, e.g
• Double negative
• This makes a censor tenser
• You shouldn't do it
• Eating peas with a knife, e.g
• Taboo, to tots
• It's out of bounds

Wiktionary Word definitions in Wiktionary
n. (alternative spelling of no-no English)