Bikers and Couriers

Bikers noun - Originally a British youth subculture that evolved out of the teddy boys in the 1960s; wore black leather jackets and jeans and boots; had greased hair and rode motorcycles and listened to rock'n'roll; were largely unskilled manual laborers.

Couriers and bikers are semantically related. In some cases you can replace term "Couriers" with "Bikers", this nouns are similar.

Bikers and couriers are semantically related. You can use "Bikers" instead a noun "Couriers".