Suppose a speaker says, “I shall not set foot in so-and-so’s house.” Literally, this concerns placement of a foot, but the established idiom ordinarily means not entering the house. Someone might cross a threshold without placing a foot in a particular spot; that subtlety need not govern the idiom.
«وحقيقة مهجورة»
And a literal usage that has fallen out of ordinary use.
This is abandoned literal usage: the bare sense is physically conceivable, but ordinary expression uses the phrase for entry. The relevant conventional meaning, rather than a hyper-literal foot movement, guides interpretation.