If "smoldered" refers to a fire:
* Burned brightly: This implies a visible and active flame.
* Flamed: This emphasizes the intensity and visibility of the fire.
* Exploded: This implies a sudden and powerful release of energy.
* Extinguished: This means the fire has been put out completely.
If "smoldered" refers to suppressed emotions:
* Expressed: This means openly showing or communicating feelings.
* Exploded: This implies a sudden and intense release of emotions.
* Erupted: This suggests a sudden and powerful outburst of emotion.
* Calmed: This means the emotions have been subdued or controlled.
If "smoldered" refers to a slow burning anger or resentment:
* Forgiven: This implies letting go of anger and resentment.
* Reconciled: This means resolving conflicts and coming to an understanding.
* Appeased: This suggests that anger has been calmed or satisfied.
Other possible antonyms:
* Sparkled: This implies a bright and lively expression of emotions.
* Bloomed: This suggests a gradual and positive development of feelings.
The best antonym for "smoldered" will depend on the specific context of your sentence.