traffic vs slave trade

traffic and slave trade both are nouns.

Word	Noun	Adjective	Verb	Adverb
traffic	Yes	No	Yes	No
slave trade	Yes	No	No	No

As nouns, slave trade is a hyponym of traffic; that is, slave trade is a word with a more specific, narrower meaning than traffic:

traffic: buying and selling; especially illicit trade
slave trade: traffic in slaves; especially in Black Africans transported to America in the 16th to 19th centuries

Other hyponyms of traffic include drug traffic, drug trafficking, narcotraffic, barratry, simony, slave traffic.

traffic (noun)	slave trade (noun)
buying and selling; especially illicit trade	traffic in slaves; especially in Black Africans transported to America in the 16th to 19th centuries
social or verbal interchange (usually followed by `with')
the amount of activity over a communication system during a given period of time
the aggregation of things (pedestrians or vehicles) coming and going in a particular locality during a specified period of time

traffic (verb)	slave trade (verb)
deal illegally
trade or deal a commodity