The word disingenuous is a 17th century English formation from the prefix dis- ("not") and the word ingenuous.  Ingenuous, in turn, comes from the Latin ingenui, meaning "freeborn". The Romans linked "freeborn" to positive qualities like honesty and straightforwardness, so disingenuous literally means "not honest" or "dishonest," referring to someone who lacks candor or frankness.  

According to the Oxford English Dictionary (OED), the adjective "disingenuous" was first used in 1648. The OED's earliest evidence comes from the writings of Joseph Beaumont, an English poet and college head. 

Examples of "disingenuous" used in a sentence: 
"I thought both men made some good points and both said some evasive, disingenuous things." 
"To single out Moore in an age of mind-numbing folksiness in politics is disingenuous." 
"So to say that we're disingenuous in standing behind the defense is absolutely wrong." 
"The press's coverage of health care and accessibility issues is disingenuous at best." 
"The governor's objections are disingenuous at best." 
"This is why we are urging stockholders to avoid being misled by what amounts to a contradictory and disingenuous ploy." 

Just the facts:

DISINGENUOUS Definition & Meaning - Merriam-Webster

DISINGENUOUS Synonyms: 72 Similar and Opposite Words | Merriam-Webster Thesaurus