the word 'thyself' is a compound pronoun formed within old english, combining the possessive pronoun 'thy' with the noun 'self'. 'thy' originates from the proto-germanic reflexive possessive base þīnaz, which is also the source for the modern 'your' (singular). 'self' has deep proto-germanic roots (selbaz) and is related to the concept of sameness or identity. the compound served as an emphatic or reflexive form for the second person singular, mirroring the construction of 'myself'. its usage has largely faded from modern standard english, preserved primarily in religious texts, historical contexts, and certain dialects, where it emphasizes the individual being addressed.

Structure: thy (your) + self (own person) thy (from middle english 'thi', old english 'þīn', meaning 'your' - singular, genitive case); self (from old english 'self', meaning 'one's own person, same').