Plesionym

It was suggested in 12.1 that propositional synonyms are 'more synonymous' than plesionyms, which, in turn, are 'more synonymous' than non-synonyms.

An immediate question is when does a plesionym cross a "vertical distance boundary" to become a different concept?

Such a semantic intertextual frame arises when the lexical item 'mist' is linked to its plesionym 'fog' and an intertextual link between two texts containing these lexical items is created.

A word is a plesionym if it is a near-synonym, but substitution of the word does not leave the same truth conditions. For example, it 'It wasn't misty, just foggy', the words 'misty' and 'foggy' are pleisonyms of each other. […] Plesionyms are often used to indicate that the speaker is grappling after precision, but perhaps does not possess the precise vocabulary or technical term for the object in mind.