I tried to teach about oxymorons, when I was teaching in Japan.
The other teachers just bombarded me with the ‘joke’ oxymorons like ‘Microsoft works’ and ‘airline food’. I never actually found these funny.
I just wanted a list of them. I like ones like
-deafening silence
-cruel kindness
-mindless thinking
which I think say something interesting.
Case in point: most of those joke ones aren’t actually oxymorons! They’re “contradictions in terms”. An oxymoron are two terms whose meanings are different/opposite in the context of the sentence. So ‘jumbo shrimp’ isn’t one because “shrimp” in this context isn’t being used as an adjective to mean “small”. And ‘pretty ugly’ isn’t one because “pretty” doesn’t mean “beautiful” in this context.
Also, neither of those can be considered oxymorons because the juxtaposition isn’t intentional for literary effect. Gah! It annoys me to no end to hear people say “heh heh: military intelligence is an oxymoron, you know.”
(As a converse rule to the one you propose: the really popular false oxymorons can’t be uttered without someone in the crowd shouting “Hey! That’s an oxymoron!”)
And when people call non-linguistic objects “oxymorons,” that really frosts my pumpkin (e.g. “The character of Hamlet is an oxymoron because he behaves so differently at different times.”)
And as further proof that it’s impossible to discuss them without citing all the bad ones, here’s wiki’s list of fake ones:
civil libertarian
anecdotal evidence
inductive logic
Larger half
Pretty ugly
wicked nice
deafening silence
Jumbo shrimp
Is this the right room for an argument?
-Monty Python
IANA poet, but Shakespeare was. Here are some oldies-but-goodies:
tragical mirth (MSND)
Feather of lead, bright smoke, cold fire, sick health (R&J)
sweet sorrow (R&J)
cruel kindness (Ham)
dearest enemy (HIV)
fearful bravery (JC)
pleasing punishment (CoE)
Of course, context is important for determination of oxymorons, and I’m not providing context. So you’ll have to trust me on that count. People were much more enthralled by the idea of oxymoron in Elizabethan times, so their use was much more common.