Hard-core and Low-down

Hard-core adjective - Firmly established over time.

Low-down and hard-core are semantically related In some cases you can use "Low-down" instead an adjective phrase "Hard-core".

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

Hard-core and low-down are semantically related in sexually aroused topic. Sometimes you can use "Hard-core" instead an adjective phrase "Low-down".