Antipode and near antipode? Antonyms and near antonyms? Do they sound good and "technical enough" for your paper?
Palinkasocsi“The problem this time is that perhaps BOTH types of pairs (wonderful-lousy; alive-dead) could be termed: to be in opposition. I just wanted to find exclusive terminology for these different groups. That is terminology allowing no transitions between the two types.”
In my opinion, this kind of demarcation is arbitrary and artificial. Whether two terms are exact, near exact or not opposite in meaning often depends on context.