The Collaborative International Dictionary of English v.0.48:
Tag-rag \Tag"-rag`\, n. & a. [See Tag an end, and Rag.] The lowest class of people; the rabble. Cf. Rag, tag, and bobtail, under Bobtail. [1913 Webster] If the tag-rag people did not clap him and hiss him, I am no true man. --Shak. [1913 Webster]