An idiom is a phrase that makes no sense unless you know the definition. Can a nose actually run somewhere? No, so this is an idiom.
It is not an idiom, it means your nose is itching.
If you are exhausted but keep going anyway, you are running on empty.
It's not an idiom because you can figure out the meaning if you think - if you're running around in circles, you're not getting anywhere. It's a metaphor for fruitless work.
It either means to hit someone on their nose, or if it's an idiom, it means to hit something dead on, or to get something exactly right.
The idiom 'sands of time' refers to the inexorable forward movement of time. It refers directly to the sand running through an hourglass.
It is not an idiom, it means your nose is itching.
say no to it
While both running nose and runny nose are correct, the preferred term is runny nose. A running nose is a specific instance of the event.
To poke your nose into is to insert yourself into someone else's business.
the runaround
If your nose is "running," then you have a mucus discharge. The image is of the mucus running out of your nose so that you need a tissue or you need to blow the mucus out.
If you are exhausted but keep going anyway, you are running on empty.
From horse racing, where they judge the winner of the race by which horse's nose crosses the line first.
It's not an idiom, it's a description. It's when you bleed from your nose.
It's not an idiom because you can figure out the meaning if you think - if you're running around in circles, you're not getting anywhere. It's a metaphor for fruitless work.
The most common phrase is "nose to the grindstone," as in "He really has his nose to the grindstone this week."
The idiom for paying far more for an article than it is really worth is "to pay through the nose."