Lacking the power or faculty of speech
Temporarily unable or unwilling to speak, as from shock or fear
Gabriel was speechless for a long moment.
Stunned, he was speechless for a long moment.
We traipsed up the stairs to the living room, a parade of zombies, each as stunned and speechless as the others.
For the first time in his life, Damian was speechless when confronted with the horror before him.
Speechless, Rhyn's heart flip-flopped at the prospect of seeing his mate again.