national leader vs pol

national leader and pol both are nouns.

Word	Noun	Adjective	Verb	Adverb
national leader	Yes	No	No	No
pol	Yes	No	No	No

As nouns, pol is a hypernym of national leader; that is, pol is a word with a broader meaning than national leader:

national leader: a person who is a respected leader in national or international affairs
pol: a person active in party politics

Other hypernyms of national leader include political leader, politician, politico.

national leader (noun)	pol (noun)
a person who is a respected leader in national or international affairs	a person active in party politics