If you are gullible, the joke is on you because you are easily fooled.

It is thought that gullible might be derived from the verb gull, meaning "to swallow." This would be a funny coincidence as gullible describes an overly trusting person who tends to swallow the stories he hears whole. The related word, gull, can be used as a noun "don't be such a gull!" or as a verb "you can't gull me into believing that!"

Definitions of gullible

adj naive and easily deceived or tricked

“at that early age she had been gullible and in love”
fleeceable, green
naif, naive
marked by or showing unaffected simplicity and lack of guile or worldly experience

adj easily tricked because of being too trusting

gullible tourists taken in by the shell game”
not alert to danger or deception

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