Smolder (verb)

1. Burn slowly without flame, typically producing smoke.
2. Suppress one's feelings or reactions, especially anger, resentment, or passion.

Origin:

Old english smoldrian, of germanic origin; related to german schmauchen, dutch smeulen.

Examples:

1. The logs smoldered in the fireplace, producing a warm glow.
2. The fire smoldered for hours before breaking out into flames.
3. She smoldered with anger after reading the letter.
4. His smoldering gaze made her heart race.
5. The embers smoldered long after the fire went out.