Part of Speech: Noun
In a broader sense, "championship" can also refer to the act of supporting or advocating for something or someone. For example, "Her championship of the arts helped secure funding for the local theater."
There aren’t specific idioms that include "championship," but you might hear phrases like "in the championship round," which refers to the final stage of a competition.
There aren't common phrasal verbs directly related to "championship," but you might say "go for the championship," which means to strive to win the title.
"Championship" is a noun that signifies a competition to determine the best or a state of being a champion.