Compound phrases are only obvious if you know the context they inhabit. Perhaps in an alternate timeline, "vaccine passport" is the practice of traveling abroad for the purpose of getting medical care unavailable in your own country (what we here on ol' Earth-616 refer to as medical tourism[0]); in yet another timeline "vaccine passport" means an actual evil-Bill-Gates style ID-nanochip injected into you and required for travel.

Similarly, alt-Earth's "bit rot" is an equine gum disease, "air fryer" is a slang synonym for a smoking-fast fastball; and so on.

Anyway, part of the usefulness of dictionaries is to preserve today's meaning for posterity, when what consider to be obvious context may no longer be widely known. The Dictionarium Anglo-Britannicum, one of the earliest English language dictionaries from 1708, included compound phrases like the "Ropes of a Ship," which meant pretty much exactly what you would think it meant, but also phrases like "Equivocal Generation"[1] which might sound to contemporary ears like it's referring to hipsters or something, but actually means something totally different.

[0]https://dictionary.cambridge.org/us/dictionary/english/medic...

[1]https://en.wikipedia.org/wiki/Spontaneous_generation