Sans means without. English borrowed the little word from French, and you can still hear the French on it, so it does not sound like ordinary “without”. People mostly use it with a small smile — in a caption, a joke, a slightly dressed-up sentence: he arrived sans jacket, the cake came sans cream. It is not the word you want in a school essay or at the shops; there, say without. You will also meet it in sans-serif, the name for letters with no little feet on them — same idea: without. Older English used it more seriously; today the serious use is rare, and the playful one is the one students actually see.