the objective case of whoso.
pronoun; objective whom·so.
Origin of whoso
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for whomso
Historical Examples of whomso
Beetles and snuff-boxes may be but small gains, but gains they are to whomso desires them: and gain is gain, however small.Browning and Dogma
Ethel M. Naish
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012