Idioms Z
 Zero hour  The time when something important is to begin is zero hour
 Zero tolerance
 If the police have a zero tolerance policy, they will not overlook any crime, no matter how small or trivial
 Zigged before you zagged  If you did things in the wrong order, you zigged before you zagged
 Zip it  This is used to tell someone to be quiet
 Zip your lip  If someone tells you to zip your lip, they want to to shut up or keep quiet about something