On no account phrase informal
Sometimes written as "Not on any account". If something should on no account be done, it should not be done under any situations.
On no account give Peter an apology. You've done nothing wrong.
The girl left on no account.
You must on no account give your personal details to anyone over the phone or by email.
To know and understand a situation only when it has already happened
Completely controlling over a scenario or situation.
The existing situation or condition
If there's a rumor about someone or something, there must be a good reason for it.