DUMBFOUND is validvalid

[v DUMBFOUNDED, DUMBFOUNDING, DUMBFOUNDS] : DUMBFOUNDINGLY [adv]

97,303 of 196,601 in NWL2023·also valid in CSW24

to strike dumb; to confuse with astonishment, also DUMBFOUNDER, DUMFOUND, DUMFOUNDER [v -ED, -ING, -S]