The antonyms for the word "more mirthless" are abundant. Mirthless means lacking in enjoyment or amusement, so the opposite of that would be extremely varied. It could be lively, joyous, hilarious, humorous, gleeful, entertaining, fulfilling, pleasurable, exciting, amusing, or cheerful. In contrast to mirthless which implies a sense of sadness, these antonyms describe activities or situations that bring a lot of happiness, laughter or smiles. Together, they showcase the vast range of emotions that people experience in a lifetime, from moments of deep sorrow, to times of incredible joy and happiness.