Nothing could be further from the truth

Question

This line is from The last ship movie where the president of the United States of America issues a video message to the remaining population, trying to put an end to the rumors that have spread out against the cure:

Nothing could be further from the truth.

I wonder if he could have said instead:

Nothing could be far and away from the truth.

Grammar Girl says:

The quick and dirty tip is to use “farther” for physical distance and “further” for metaphorical, or figurative, distance. It's easy to remember because “farther” has the word “far” in it, and“far” obviously relates to physical distance.

Now that my proposition contains the word far would seem that the replacement is wrong as it's not about a physical distance but Merriam Webster gives the following example:

that Mexican restaurant is far and away the best in the area

where the word far is contained although it's not about a physical distance.

So, my question is: are further and far and away synonymous and if so are they always interchangeable?

Answer 1

No, they're not synonymous and they're not interchangeable.

"Nothing could be further from the truth" is a polite way of saying that something is an outrageous lie or a gross error. The meaning is literal: the statement you are referring to is not just untrue, but it is as far from the truth as you can imagine. It's something of an idiom, I guess, or at least, it's a stock phrase.

"Far and away" is an idiom used to indicate that something is not only the most in some category, but that all competitors are far behind. It is normally followed by the word "the" and a superlative. It could be something positive or something negative. Like, "Al is far and away the fastest runner in the world." That is, not only is Al a fast runner, not only is he the fastest runner in the world, but no other runner even comes close to his speed. "Betty is far and away the biggest cheater I have ever met." Not only is Betty a cheater, but no one else cheats anywhere near as much or as brazenly as she does. Etc. Such a statement may be meant literally: in my first example, Al may have just won an Olympic race leaving all his opponents far behind. Or it may be a poetic exaggeration. Al isn't really an Olympic gold medal winner, I just want to emphasize that he's really fast.

You can't substitute because "far and away" is part of an idiom. You can't rip it out and use it without a superlative. "Nothing could be far and away from the truth" doesn't make sense. Even if you take "far and away" to mean "very far", still, this would say that it is not possible for anything to be very untrue, which isn't what the speaker is trying to say at all. He's trying to say that the referenced statement IS very untrue.

Answer 2

Further and far and away are not interchangeable.

Further by itself only means a greater distance which may be large or small in comparison

Tokyo is further than London from New York
He lives further along in the next house

The expression nothing could be further from implies a very great distance

Nothing could be further from

1) Nothing could be further from the truth.
2) Nothing could be far and away from the truth.
3) Nothing could be far and away further from the truth
4) Far and away that is the biggest lie.

#1 is the understood expression
#2 is incorrect
#3 could be understandable as meaning #1
#4 may have the same meaning as #1 however #1 is in reference to a truth which is being sought

Far and away is a superlative meaning very much or most where there is a great distance or distinction with the next place. You can think of using very much interchangeably.

that Mexican restaurant is the best in the area, the second best is almost as good

that Mexican restaurant is far and away the best in the area, the second best doesn't even come close

that Mexican restaurant is very much the best in the area

However, native speakers will use the shortened idiomatic expression

that Mexican restaurant is the best in the area by far