Igneous and Red hot

Igneous adjective - Produced by the action of fire or intense heat.

Red hot and igneous are semantically related In some cases you can use "Red hot" instead an adjective "Igneous".

Red hot noun - One who is intensely or excessively devoted to a cause.

Igneous and red hot are semantically related in passionate topic. Sometimes you can use "Igneous" instead an adjective phrase "Red hot", if it concerns topics such as hot.