My brain popped up with that word or phrase, s'habille, while I was on my way to a meeting. My brain is telling me it means something like, "in order to be well turned out, dressed to be able to perform a particular function well". In other words, a functional outfit that is quite appropriate to what you are doing or trying to do. A chef wears a certain hat, and usually a sort of uniform, often an apron.
I have looked through Google to see if this is what it means, but I did not see the particular form of the word/words.
How far off are the brain cells?