This idiom refers to being easily deceived or fooled by something trivial or superficial, often due to inexperience or gullibility. It evokes the image of a bird caught by chaff (grain husks) instead of real food, and is used to describe someone tricked by a ruse or distracted by something worthless.

The phrase likely stems from 16th-century English rural life, where farmers used chaff to lure birds into traps, exploiting their inability to distinguish it from grain. It appeared metaphorically in William Shakespeare’s *Othello* (1604), where Iago speaks of deceiving someone ‘with chaff.’ By the 17th century, it was a proverb for gullibility, as seen in John Ray’s 1678 *English Proverbs*. Its use declined in modern English but persists in literary or historical contexts, reflecting themes of deception and naivety.