The popular idiom "hold the fort" or "hold down the fort" means to watch, manage, or protect an area while the speaker making the request is away.
I think it means that that person agrees with that others persons idiom and that it fit that question that the teacher or whoever asked that question.
To hope for the best
It was a phrase. "Hold on to your hat, there is going to be a bumpy road ahead"!
The idiom "to hold water" means that an argument, theory, or idea is sound, valid, or credible. It suggests that the reasoning or evidence presented is strong enough to withstand scrutiny. If something does not hold water, it indicates that it is flawed or unconvincing.
It means you refrained from saying something
To be tightfisted means that you hold on to your money. You're cheap.
"Hold your tongue" means don't just say what comes to mind - or think before you talk.
George Washington
You cannot stand on the beach and hold back the tide is both an analogy and a metaphor.
Idiom is correct.
It just means they smiled. Perhaps they were trying to hold back a smile, but they grinned nonetheless.
Because the South wanted to assert that this island-fort in Charleston harbour was part of the Confederacy. The Union did not recognise the Confederacy, and tried to defend the fort as one of its own garrisons.