zero in on
‘Zero in on [something]’ can mean any of the following:-
- converge on [something]
- aim at [a target] precisely
- focus one’s attention on [a task]
- narrow down a search for [something] successfully
zero tolerance
The phrase ‘zero tolerance’ is used in reference to ‘a form of policing that does not allow any anti-social behaviour or crime to be overlooked‘.
zonk out
The phrase ‘zonk out’ has two meanings.
One of its meanings is ‘fall asleep fast due to extreme tiredness‘.
The other meaning is ‘lose consciousness following a sudden trauma‘.