To him this is a deadly blow.

As long as it's not a fatal mistake, it is ok to fail.

So it seems that cloud of odorless deadly gas had a silver lining after all.

You can't seriously expect that they won't recognize you in that disguise. That lopsided, dime store moustache is a dead giveaway!

A slip of the tongue is sometimes fatal to a politician.

Ebola is one of the most virulent viruses known to man.