obmutescent
/ˌɒbmjuːˈtɛsnt/literary. rare
adjective
Speechless; remaining mute.
Origin
Late 18th century; earliest use found in Monthly Mirror. From classical Latin obmūtēscent-, obmūtēscēns, present participle of obmūtēscere to become dumb or mute from ob- + mūtēscere to grow mute from mūtus + -ēscere.