kingpin vs bowling pin

kingpin and bowling pin both are nouns.

Word	Noun	Adjective	Verb	Adverb
kingpin	Yes	No	No	No
bowling pin	Yes	No	No	No

As nouns, bowling pin is a hypernym of kingpin; that is, bowling pin is a word with a broader meaning than kingpin:

kingpin: the front bowling pin in the triangular arrangement of ten pins
bowling pin: a club-shaped wooden object used in bowling; set up in triangular groups of ten as the target

Other hypernyms of kingpin include pin.

kingpin (noun)	bowling pin (noun)
bolt that provides a steering joint in a motor vehicle	a club-shaped wooden object used in bowling; set up in triangular groups of ten as the target
the front bowling pin in the triangular arrangement of ten pins
the most important person in a group or undertaking