The word 'whosoever' is a compound pronoun formed in Middle English by combining three distinct Old English elements. It is an emphatic and archaic variant of 'whoever', built from the interrogative pronoun 'who', intensified by the adverbs 'so' and 'ever'. The construction follows a pattern common in older stages of English, where 'so' and 'ever' were appended to question words (like 'what', 'which', 'who') to create indefinite or universal pronouns meaning 'any person that' or 'no matter who'. Over time, 'whosoever' has become largely restricted to formal, legal, or religious contexts, preserving its sense of absolute inclusivity.

Structure: who + so + ever - who (Old English: 'hwā', interrogative/relative pronoun) - so (Old English: 'swā', adverb meaning 'in this way, to such a degree') - ever (Old English: 'ǣfre', adverb meaning 'always, at any time')