The definition of a Johnny-come-lately is a newcomer, or is someone who is late to accepting a position or late to arriving at an event.(noun)
A newcomer to an idea who is late in accepting what everyone else already believes to be true is an example of a Johnny-come-lately.
See Johnny-come-lately in Webster's New World College Dictionary
noun pl. Johnny-come-latelies
See Johnny-come-lately in American Heritage Dictionary 4
noun pl. John·ny-come-late·lies or John·nies-come-late·ly (jŏnˌēz-)
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