Entry 1 sense Webster, 1913 Solemnly /sôl'-əm-lē/ · Sol·emn·ly · IPA /ˈsɑləmli/ 01 adv. In a solemn manner; with gravity; seriously; formally. 1. In a solemn manner; with gravity; seriously; formally. “There in deaf murmurs solemnly are wise.” — Dryden. “I do solemnly assure the reader.” — Swift.