Diametrically opposed and Old-line

Old-line and diametrically opposed are semantically related. In some cases you can use "Old-line" instead an adjective phrase "Diametrically opposed".

Old-line adjective - Tending to favor established ideas, conditions, or institutions.

Diametrically opposed and old-line are semantically related. Sometimes you can use "Diametrically opposed" instead an adjective phrase "Old-line".