sarg
miserable
(Swiss, colloquial, very rare) Bad, wretched, or miserable.
Nach der langen Krankheit war ihm ganz sarg zumute.
After the long illness, he felt completely miserable.

miserable
Loading your saved state.
miserable
(Swiss, colloquial, very rare) Bad, wretched, or miserable.
Nach der langen Krankheit war ihm ganz sarg zumute.
After the long illness, he felt completely miserable.

This word is very rare and is used exclusively in Swiss colloquial speech. In Germany and Austria, it is unknown and would probably be confused with the noun 'der Sarg' (coffin).
Nach der schlechten Nachricht war ihm den ganzen Tag sarg zumute.
After the bad news, he felt miserable all day.
The adjective 'sarg' (miserable) is typically used in the fixed expression 'jemandem ist sarg zumute' (someone feels miserable) to express a feeling of dejection or misery. The person is in the dative.
Mir ist heute irgendwie sarg zumute, ich bleibe lieber zu Hause.
I somehow feel miserable today; I'd rather stay at home.
The meaning 'elend' (wretched) or 'miserabel' (miserable) can be derived from the noun 'der Sarg' (coffin). The idea is to feel so bad that it is as if you were already lying in a coffin.
Warum schaust du so sarg drein? Ist etwas passiert?
Why do you look so miserable? Did something happen?
good
'gut' and 'sarg' can theoretically be opposites if 'sarg' is used in the sense of 'schlecht' (bad), 'elend' (wretched), or 'miserabel' (miserable). 'gut' is a completely normal and very common word for something positive. 'sarg', on the other hand, is Swiss, colloquial, and very rare. Most German learners will hardly need this word. In normal everyday language, the opposite of 'gut' is almost always more naturally expressed with 'schlecht', or, depending on the situation, 'mies'.

Nach dem Spiel war die Stimmung im Team sarg.
After the game, the mood in the team was miserable.
Ihr seid vor der Reise gut vorbereitet.
You are well prepared before the trip.