say it: KING-pin
kingpin is a noun meaning "the most important person in a group or undertaking". It carries 3 recorded senses.
the most important person in a group or undertaking
bolt that provides a steering joint in a motor vehicle
the front bowling pin in the triangular arrangement of ten pins
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for kingpin come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.