"Unctuous" essentially just means "oily, but it's a good thing." But since that's a pretty rare property for a food to have, there aren't many ways to say it, or things to say past just "unctuous" — which makes it seem kind of opaque and ritualistic as a descriptor.
It's similar to how we have a lot of ways to describe things smelling bad, but relatively few words to describe things smelling good beyond "fragrant" or maybe "aromatic."
> 1: having, revealing, or marked by a smug, ingratiating, and false earnestness or spirituality
> 2
> a: FATTY, OILY
> b: smooth and greasy in texture or appearance
> 3: PLASTIC
I’m aware of the definition. My experience with the word has primarily been under the 1st definition, so the positive connotation that food writers have been using it with seems absolutely ridiculous to me. Especially when I would use the first definition to describe the work of many food critics (maybe it’s an attempt at reappropriation :P).
I don’t mean this in a harsh way, but using unctuous to describe “oily but good” properties just seems ignorant. I hear “unctuous” to describe a fried pizza the OP enjoyed, and think “slimy sales person” or “The Blob”.
I also get that language is fluid as groups repurpose words. I’m just not a fan of this one. Current usage screams that some food writer pulled the word out of a thesaurus instead of their vocabulary and somehow it started to stick.
The food (or just literal "oil") sense came first, though; unctuous has always been a sensory texture word. It wasn't always a positive quality, mind you; it's just one of several normal words you could use to call something "oily" in Latin. From Etymonline:
> late 14c., "oily, having a greasy or soapy feeling when touched," from Old French unctueus, from Medieval Latin unctuosus "greasy," from Latin unctus "act of anointing," from past participle stem of unguere "to anoint" (see unguent).
> Figurative sense of "blandly ingratiating" is first recorded 1742, perhaps in part with a literal sense, but in part a sarcastic usage from unction in the meaning "deep spiritual feeling" (1690s), such as comes from having been anointed in the rite of unction. Related: Unctuously; unctuousness.
(Which is to say: there are probably Bible translations from before the sarcastic personality sense developed in the 1700s, that use the word "unctuous" as an adjective for the same effect that we'd today use the word "anointed.")
It's kind of fascinating that the word "unctuous" has acquired positive connotations with respect to food, from starting off as a relatively neutral descriptor. I think it's maybe a rare reversed example of the common connotative shift that happens over time, where if there's a "high [language]" word (usually a foreign import that sounds fancy and technical at the time of its introduction) and a "low [language]" word (usually a native or much older borrowed word) for something, then the "low [language]" word will acquire negative or rude connotations to speakers of that language. E.g. the difference in propriety in English between writing "I'm eating pork" vs "I'm eating pig"; or between writing "feces" vs "dung."
It's similar to how we have a lot of ways to describe things smelling bad, but relatively few words to describe things smelling good beyond "fragrant" or maybe "aromatic."