Lowborn and Second class

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

Second class and lowborn are semantically related In some cases you can use "Second class" instead an adjective "Lowborn".

Second class noun - Not the highest quality in a classification.

Lowborn and second class are semantically related in poor topic. Sometimes you can use "Lowborn" instead an adjective phrase "Second class".