dumb·found also dum·found (dŭmfound′)
tr.v. dumb·found·ed, dumb·found·ing, dumb·founds also dum·found·ed or dum·found·ing or dum·founds
To fill with astonishment and perplexity; confound. See Synonyms at surprise.
[DUMB + (CON)FOUND.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.