She keeps Moet and Chandon in her pretty cabinet
'Let them eat cake' she says
Just like Marie Antoinette

As I would guess (and I would be right) that everyone knows the famous line, 'let them eat cake'? Coined by Marie Antoinette, after she was informed that the poor were starving because they had no bread to eat, she said "Let them eat cake"... cause she was such a ditz she was guillotined during the French revolution. It also indicates that our Killer Queen is not only rich she's also a ditz

A built in remedy for Khrushchev and Kennedy
And anytime an invitation you can decline

This woman has a remedy for everything, denoting her arrogance.

Caviar and cigarettes well versed in etiquette
Extr'ordinarily nice

This is the disguise part. This woman sounds like a bit of a ponuce, doesn't she? PS You think they're opium cigarettes?

She's a killer queen gunpowder gelatine

Ok, everybody. She's a Killer Queen, because she deals drugs which can possibly kill people [ie drug overdoses]. Gunpowder is cocaine and gelatine denotes the gelatine which usually covers capsules..

Dynamite with a lazer beam
Guaranteed to blow your mind
Recommended at the price
Insatiable an appetite wanna try?

Now, if that isn't about drugs, I don't know what is. 'Recommended at the price.... wanna try?'. Give me a break!

To avoid complications
She never kept the same address

This means that she was always on the run from the law, as you do.

In conversation she spoke just like a baroness

The last two lines try to provide a contrast between someone who's always on the run yet they're always composed.

Met a man from China went down to Geisha Minah
Then again incidentally if you're that way inclined (she's a killer queen)

OK, let me get this straight, GEISHA MINOR is TURKEY. I don't know what the whole MINAH thing is indicative of, it can possibily be a euphemism for a shady establishment, frequented by KQ.

Perfume came naturally from Paris (naturally)
For cars she couldn't care less
Fastidious and precise

LOL, Freddie never learnt how to drive. It's like me never dotting my eyes cause of BQ...

She's a killer queen gunpowder gelatine
Dynamite with a lazer beam
Guaranteed to blow your mind
Recommended at the price
Insatiable an appetite wanna try?

Drop of a hat she's as willing as a playful as a pussy cat
Then momentarily out of action
Temporarily out of gas
To absolutely drive you wild - wild
She's out to get you

This refers to the drug induced haze that this woman has. Because my brother is a pharmacist, he knows all about this stuff. When a person takes a vast amount of drugs they have major swing moods, so that would make sense in this verse 'then momentarily out of action' to 'absolutely drive you wild'. It also indicates the rush yet grace and composure KQ had. V graceful, yet v wild!

She's a killer queen gunpowder gelatine
Dynamite with a lazer beam
Guaranteed to blow your mind
Recommended at the price
Insatiable an appetite wanna try?

Wanna try

O well, so the real meaning is exposed. Still doesn't mean it's a great song, because it is. Wow, go Killer Queen! WOOHOOO!!!