The French loanword sans is a slightly fancy but appealingly quick way to say without. Careful writers who value unaffected prose are likely to use without instead of sans, but there is nothing wrong with using sans if you like the way it sounds. Though it’s originally French, it has a long history of use in English. The Oxford English Dictionary lists examples in English from as long ago as the 14th century, but the word was not widely used until the early 19th century.
In French, the s at the end of sans is usually silent. English speakers often pronounce it.
The men wore their kilts in the traditional Scottish manner – sans undergarments. [New York Daily News]
Perry hurtled through her hits, although weirdly the mighty Firework came and went sans actual fireworks. [This is London]
On the Conservative Party website home page, Stephen Harper is seen several times in a jacket but sans tie. [CTV.ca]