'splayed-toed' is a modern compound formed from the past participle 'splayed' (from the verb 'splay') and 'toed' (the adjectival form of 'toe'). 'splay' derives from Middle English words related to spreading, and 'toe' comes from Old English 'tā', meaning 'digit of the foot'.

'splay' changed from Middle English forms such as 'splayen' (meaning 'to spread') and 'toe' from Old English 'tā'; the compound adjective 'splayed-toed' developed in modern English by combining these elements to describe the position of toes.

Initially, 'splay' meant 'to spread' and 'toe' meant 'digit of the foot'; over time the combined form came to mean 'having the toes spread outward' in descriptive usage.