I thought it was pronounced mar-kee.

Mar-kess or mar-key

never mar-kwis

I would also say marquis but I can only think of de Sade as an example of one

*markee

I thought mar-kess was female and mar-kwis was male?

Mar-kee being French...

More mahkee

markey is French

Marchioness is female 

Marquis of Bath of the murals and lions

Ok kwis then

I would say markee de sade cos it's foreign 

it was always the marqwis of Worcester when I lived in forelock tugging parts 

I say markess but it was part of the name of a pub next to my old office and that's what everyone else said.

https://www.bbc.co.uk/programmes/p021lnyx

Radio 4 programme

hmmmm this seems to agree with me: https://dictionary.cambridge.org/pronunciation/english/marquis

Paging Clubbers

If a non historical figure they can have Mr, Ms or Dr and like it. 

Mar-kwis in English, as in the Marquess of Queensberry

No idea what forrins do

To be honest, I’m taking my ‘knowledge’ from the pub The Marquis of Granby.

aaahhh but Dux, in that radio programme, it was the M of Queensberry to whom they referred as Markess

I think I say more markwess.

I suspect the narrator was either a Septic or a continental of some sort.

Then they are ignorant

Markess of Bath?

TrafulGAR ?

Roeboe ?

etc etc 

Scion catches the unwary tho. Probably because normal people never hear it pronounced

Mar-kwiss.  Or Mar-Kee if the person is forrin.

Marquess - an English title for noblemen ranking below a Duke and above an Earl and pronounced Markwess

Marchioness - the English title for the wife or widow of a Marquess, pronounced Mar-chee-onn-ess

Marquis - a French title for noblemen of similar rank to an English Marquess, pronounced Markee

Marquise - a French title for the wife or widow of a Marquis, pronounced Markeese

Markgraf - a German title for noblemen who own three pigs or more

Margravine - a German title for the wife or widow of a pig farmer

Judy, do you also say 'choritzo'?

who gives a flying fook?

I thought a ”markee” was a tent and a “markwis” was a fella with a title spelled “marquis”.  

No, Supes, I say choreetho.

I've always pronounced it "Raymond Luxury-Yacht"