Mortally afraid is an expression used to describe intense fear or terror. When looking for synonyms for this phrase, there are numerous options available. Some other phrases or words that can be used to convey the same level of fear include "panicked," "horrified," "terrified," "petrified," "frozen with fear," "fearful," "dreadful," "paralyzed with fear," and "trembling in fright." Each of these phrases can be used to indicate extreme fear, and they can be chosen depending on the context of the sentence and the level of intensity of fear being conveyed. Regardless of which synonym is used, the goal is to effectively convey the intensity of the fear being experienced by the individual.