The term "be moaning" is generally used to describe a feeling of dissatisfaction or unhappiness. Antonyms for the word include "rejoicing," "cheering," and "celebrating" -- all terms that express a sense of happiness or joy. Other potential antonyms for "be moaning" might include phrases like "praising," "uplifting," or "applauding," which all suggest a positive outlook and a focus on the good things in life rather than the bad. Ultimately, the antonyms for "be moaning" are words that express the opposite emotion, conveying a sense of satisfaction and contentment that counters any feelings of sadness or disappointment.