The word "sic" is Latin in origin and means "thus" or "so," according to the Modern Language Association (MLA) Handbook.
Inserting sic following a quote indicates "the quotation is accurate even though the spelling or logic might make [the reader] think otherwise," according to the MLA Handbook.
The use of sic tells the reader that you recognize the error or outdated spelling within the quotation, but quoted it verbatim.
When sic follows a quotation, place it in parenthesis outside the quote marks and before the final punctuation, as in: "I misplaced my checbook" (sic). To insert sic within the quotation immediately after an error or misspelled word, place it in square brackets, as in: "I misplaced my checbook [sic]."
While the MLA format does not call for sic to be italicized, some writing formats and style guides, including the APA Stylebook, do. In formal writing, refer to the appropriate format or style guide for clarification.