"Overmorrow" is actually not obscure or obsolete at all in german.
"Übermorgen" is quite often used (at least around me)

Uxorious: devoted to one's wife.

Something I learnt recently and which is rampant on gay social apps: sphallolalia - flirting that doesn't lead to meeting irl.

Defenestrate means to throw out of a window.

For example, "Someone should defenestrate Putin."

Lugubrious - because it means the opposite of how it sounds!

It's fun to say, but is defined as sadness, which the word can't evoke

Salitter is my answer to this one every time.

The silence. The salitter drying from the earth. The mudstained shapes of flooded cities burned to the waterline. At a crossroads a ground set with dolmen stones where the spoken bones of oracles lay moldering. No sound but the wind.

Here, also.

Jocund: cheerful and lighthearted.

From Romeo and Juliet:

Night's candles are burnt out, and jocund day

Stands tiptoe on the misty mountain tops.

Verantwortungsbewusstsein. Let's get back to our roots.

Seems like every time you use it you'll end up having to explain what it means unless you're playing D&D

Crepuscular. Related to twilight, dimness, the golden hour.

Logoparalysis. https://lemmus.org/post/6454872