Speechless
/ˈspiːtʃ.lɪs/
adjective
Not speaking; not knowing what to say; silent, especially due to surprise, amazement, etc.
“When he walked into his surprise birthday party, he was completely speechless.”
adjective
Incapable of being spoken or uttered
Unfit or not permitted to be spoken or described.
Extremely bad or objectionable.
“an unspeakable fool”
Synonyms: ineffable, inexpressible, unutterable