Lowborn and Low-down

Lowborn adjective - Belonging to the class of people of low social or economic rank.

Low-down and lowborn are semantically related. In some cases you can use "Low-down" instead an adjective "Lowborn".

Low-down adjective - Not following or in accordance with standards of honor and decency.

Lowborn and low-down are semantically related. Sometimes you can use "Lowborn" instead an adjective phrase "Low-down".