The word "faux" comes from French where it means "false" or "fake".  It entered the English language as a borrowing from the French word, which itself ultimately comes from the Latin word "falsus," meaning "deceived" or "misled", the past participle of fallere ("to deceive").   

The word "faux" was first used in English in the late 1600s, with the Oxford English Dictionary (OED), citing its earliest known use as 1684, in the writing of Thomas Otway. It was used earlier in hyphenated terms, such as "faux-prude," first appearing in 1676, according to the OED. Its modern use to mean "fake" or "imitation" becoming popular in the 1980s.  The expression "faux pas" (an embarrassing or tactless act or remark in a social situation) was borrowed earlier, in the second half of the 17th century, in 1676. 

Examples of "faux" used in a sentence: 
"And it was served in a faux bird's nest." 
"This faux outrage wouldn't get first place in an 8th grade talent show." 
"The black and white boots have a faux fur lining and come to mid-calf." 
"Stay warm in a faux fur coat and cinch your waist with a black and white belt." 
"At just $17, this faux leather tote is a steal too good to pass up."
"The first item to go in our cart: Spanx's faux leather leggings." 

Just the facts:

FAUX Definition & Meaning - Merriam-Webster

FAUX Synonyms: 56 Similar and Opposite Words | Merriam-Webster Thesaurus

FAUX PAS Definition & Meaning - Merriam-Webster