1) Dame counterpart 2) French title of respect 3) French title of respect, once 4) French title, old style 5) Old French title Found on https://www.crosswordclues.com/clue/sieur
Sieur noun [ French, abbrev. from seigneur. Confer Monsieur , Seignior .] Sir; -- a title of respect used by the French. Found on http://www.encyclo.co.uk/webster/S/99