There are many synonyms for the phrase "turn pale" which means to become visibly frightened, shocked or ill. Some possible alternatives include blanch, go white, lose color, become ashen, turn ashy, grow wan, pale, drain color, become colorless. These words can be used interchangeably to describe the physical reaction that occurs when someone is frightened or ill. For example, one might say "she blanched at the sight of the accident" or "he went white when he heard the news." In any case, these synonyms help to convey the intensity of the emotion and physical response associated with turning pale.