From Middle English hoe so, hoo so, hoo-so, hos, hose, ho so, ho-so, hwao-se, hwa se, hwase, hwa swa, hwo se, hwo so, oso, qhooso, qua sa, qua-so, quo so, quo-so, quuo-so, qwa se, wah-swa, wea swa, whas, whasa, whase, wha so, wha-so, wha sua, wha swa, wha-swa, whoo so, whos, whose, who so, who-so, whoso, wos, wo-se, wose, wo so, woso, wua sua, from Old English hwā swā; equivalent to who + so.
whoso (objective whomso, possessive whoseso)
- (archaic) whosoever, whatever person
1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC, Matthew 23:20-21: Whoso therefore shall swear by the altar, sweareth by it, and by all things thereon. And whoso shall swear by the temple, sweareth by it, and by him that dwelleth therein.
1866, Algernon Swinburne, Aholibah, lines 148-150: And whoso findeth by the sea
Blown dust of bones will hardly say
If this were that Aholibah.
1896, Richard Le Gallienne, The Quest of the Golden Girl: And whoso kisseth those apples high, Who kisseth once is a king, Who kisseth twice shall never die, Who kisseth thrice--oh, were it I.