topi vs sun hat

topi and sun hat both are nouns.

Word	Noun	Adjective	Verb	Adverb
topi	Yes	No	No	No
sun hat	Yes	No	No	No

As nouns, sun hat is a hypernym of topi; that is, sun hat is a word with a broader meaning than topi:

topi: a lightweight hat worn in tropical countries for protection from the sun
sun hat: a hat with a broad brim that protects the face from direct exposure to the sun

Other hypernyms of topi include sunhat.

topi (noun)	sun hat (noun)
a large South African antelope; considered the swiftest hoofed mammal	a hat with a broad brim that protects the face from direct exposure to the sun
a lightweight hat worn in tropical countries for protection from the sun