Calling anyone a "sewer" is not appropriate. I assume the words you're looking for are either 'tailor' or 'seamstress'.
1350-1400; Middle English; see sew
pronounced soh-er, not soo-er as in
sewer: an artificial conduit, usually underground, for carrying off waste water and refuse, as in a town or city.
1375-1425; late Middle English suer (e) < dialectal Old French se (u) wiere overflow channel