The primary meaning of is _disappointment_ or _disappointed_.
Dictionary says has several meanings, and there are several antonyms for for each meaning:
1. satisfied, content ⇔ **** , **** disappointed
2. proud, prideful ⇔ **** , **** embarrassed, ashamed
3. good at (e.g., tennis, math) ⇔ **** , **** bad at
That said, the primary meaning of is now "be good at" in modern Japanese. The second meaning is usually expressed with (e.g. ), and the first meaning is almost dead IMO. So I don't feel is a good antonym for . (Judging from examples here, seems to have been used in the first sense until relatively recently (approx 100 years ago)).
Perhaps more straightforward antonym for would be (satisfaction), (expectation), (hope), or such.