gaffe

gaffe    [gaf]

noun.   A embarrassing social mistake 

"If you run into a friend out with her grey-haired father, and you call him her grandfather, then you've made a gaffe."

"It was one of the most memorable gaffes:  At a GOP primary debate hosted in November 2011, former Texas Gov. Rick Perry vowed to shutter three government agencies as president, but struggled to remember the third name."

"Each of these candidates did things right and wrong in their races; some made gaffes, and others ran out of money."