Cebu City vs Cebu

Cebu City and Cebu both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cebu City	Yes	No	No	No
Cebu	Yes	No	No	No

As nouns, Cebu City and Cebu are synonyms defined as:

Cebu City and Cebu: an important seaport on the island of Cebu in the Philippines

Cebu City (noun)	Cebu (noun)
an important seaport on the island of Cebu in the Philippines	an important seaport on the island of Cebu in the Philippines
	one of the Visayan islands of the central Philippines; important for its fine harbor