OK, I get it (sort of) but I still don't know why 'brut' should be 'dry' and 'rep' should be a fabric. Is it just one of those crossword things, like 'writer' is 'me' (amongst other things!)?
Brut is French for 'unsweetened, dry(of wines)' and it's been used in crosswords quite often.
Rep is a fabric in the same way as cotton is a fabric - it's just one that you don't hear of very often!