whomso

whom·so

 (ho͞om′sō)
pron. Archaic
The objective case of whoso.

whomso

(ˈhuːmsəʊ)
pron
whomwhomsoever

who•so

(ˈhu soʊ)

pron. objective whom•so.
whosoever; whoever.
[1125–75; Middle English, early Middle English hwa swa, Old English (swā) hwā swā. See who, so1]