From mirth + -less.
- enPR: /mûrth'lĭs/, /mûrth'lĕs/
mirthless (comparative more mirthless, superlative most mirthless)
- Lacking mirth; devoid of joy.
- "The laughter of man is more terrible than his tears, and takes more forms: hollow, heartless, mirthless, maniacal..." – James Thurber