Is The Word "Liquor" Used in BrE?

Not really. As a generic term for alcoholic drink, we would use ‘booze’ or just plain ‘alcohol’. For high strength drinks we would use ‘spirits’.

The closest I get is "liqueur". Liquor's definitely something I'd only expect from an American or in US contexts, and I would assume anyone using it in the UK is either a migrant/dual-citizen or is just emulating some US personality.

Not often. We call them spirits - vodka, whisky, etc. We don't have "liquor stores", we have off-licences.

No, sounds very American to me

No, I know the word, but I wouldn't use it unless I was talking to an American. We do say "liqueur" though, but it has a different meaning. It's like a strongly alcoholic fruity drink.

I mean... We don't really use the word much in America either in day to day conversation. The only time you really ever hear it used is when referring to a "liquor store". But when talking generally about alcoholic beverages, people usually just say booze or alcohol.

It is, but it’s not as common, and tends not to be used for booze

No British English speaker would use this word in natural speech. "Spirits" would be the term used or some other more slang term.

No, not in my experience. I would think you a little weird for using it, if you were British.

Additionally, in London you get a parsley sauce called liquor on your pie and mash. It's an ancient traditional local delicacy. Nothing to do with alcohol. It's like gravy, sort of. There's a stall selling hot pie and mash with liquor in Borough Market.

What about the term "pot liquor"? Wikipedia says that's American but I'm wondering if that's known too.

No, we usually say "Spirits" to mean what Americans would call "Hard liquor" and just alcohol or booze more generally. We don't say "liquor store" for example, just "off licence" or "offy"

It's common in New Zealand