United is related to Nation. Tribe is a type of Nation. Tribe is a synonym of Folk. Folk is a synonym of People. 
Sensor is related to Nose. Nose is the opposite of Ear. 
United <--RelatedTo--> Nation <--IsA-- Tribe <--Synonym--> Folk <--Synonym--> People 
Sensor <--RelatedTo--> Nose <--Antonym--> Ear 