Gaff/gaffe

Meaning a blunder, an indiscreet act or remark and usually spelt gaffe with an e, is first attested in this sense, according to the OED, from c. 1909 and is borrowed from the French gaffe, which means a boathook as well as a blunder. It is not known how a boathook has come to mean a blunder or an indiscreet remark in both English and French, except that a gaff or boathook could perhaps be a very clumsy instrument in the wrong hands. Gaff meaning a boathook dates from the 1400s and when used in this sense is usually spelt without the e. See also blow the gaff.