smoulder(noun, verb) noun1. a fire that burns with thick smoke but no flame- the smoulder suddenly became a blazeSimilar word(s): smolderDefinition categories: event, fire verb1. have strong suppressed feelingsSimilar word(s): smolderDefinition categories: emotion, experience, feel2. burn slowly and without a flameSimilar word(s): smolderDefinition categories: change, burn, combust