Matching the words in the excerpt from Arthur Conan doyle's "The Contest" with their closest meaning:
Singular: ( unique, rare, unususal, remarkable) = strange (peculiar) "and the most singular/the strangest design."
Approbation= praise (admiration and approval of someone or something)
Mercenary (only interested in selfish gain)= flattering (making someone seem better than usual). "mercenary admirers."