Opposites
We think of ugly and beautiful as opposites, but in a sense, they are the same — they are both extremes on the spectrum of the remarkable. The opposite of them both is to be unremarkable.
This is analogous to love and hate. Love and hate are often seen as opposites, but in some sense they represent the same thing — caring strongly about something, even above oneself.
When you hate, you would sacrifice your own happiness to make another unhappy. When you love, you would sacrifice your own happiness to ensure theirs. … Okay, definitions differ, but let's use this one, for now.
So in a way, the opposite of both of them is selfishness. And in the same way, you can see all of love, hate and selfishness as being extremes of "caring strongly", and so the opposite of them all is indifference.
Is there yet another axis with all of these at one end, and something unnamed at the other?
And how far can you go in this manner?
It's nothing deep, but adding more axes either to the front or to the back can be a useful way to find things that exist, but may not have easy names.