Any deception has at it's heart, a lie. You can test this if you so choose. It just isn't explicit. If it were simple we wouldn't need lawyers.
No. It has at its heart dishonesty. A lie is an out and out untruth. Misleading, even intentionally, is not lying.
Let us pretend magical ability can be quantified simply. All people can be classified on a scale from 1 (normals) to 10 (the Merlin).
Harry says:
"The White Council has inducted all wizards of a power level 6 or greater."
"I am a level 7"
One would usually assume Harry is part of the WC.
Well, he WAS. But he is not NOW.
But what did he say was untrue?
He WAS inducted.
He IS a 7.
He did not say "All wizards of power level 6 or greater ARE part of the WC" THAT would be a lie, as he was kicked out.
If he said "The WC screens wizards, and any they find of a level 6 or up are inducted" we are led to believe all level 6 and up are, or have been, part of the WC.
But Elaine is a 6.
But she flunked her tests and they think she's a 4. Harry knows this. But he tried to mislead you.
The Fae are heartless, soulless creatures. They ARE natural lawyers. They draw these distinctions. They let you believe what they want you to believe. Whether or not it is true.