Baby's taboo

• Thing to shun
• It's verboten
• Unwise act
• Pitcher's gem, in baseball lingo
• Forbidden thing, and what each of four long answers is?
• Something that's not allowed: Hyph
• Petty taboo
• Admonition to junior
• Texting during the movie, e.g

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