Chad vs Republic of Chad

Chad and Republic of Chad both are nouns.

Word	Noun	Adjective	Verb	Adverb
Chad	Yes	No	No	No
Republic of Chad	Yes	No	No	No

As nouns, Chad and Republic of Chad are synonyms defined as:

Chad and Republic of Chad: a landlocked desert republic in north-central Africa; was under French control until 1960

Other synonyms of Chad include Tchad.

Chad (noun)	Republic of Chad (noun)
a family of Afroasiatic tonal languages (mostly two tones) spoken in the regions west and south of Lake Chad in north central Africa	a landlocked desert republic in north-central Africa; was under French control until 1960
a landlocked desert republic in north-central Africa; was under French control until 1960
a lake in north central Africa; fed by the Shari river