'non-simian' is formed from the prefix 'non-' (from Latin 'non', meaning 'not') attached to 'simian', which ultimately comes from Latin 'simia' meaning 'ape' or 'monkey'.

'simian' derives from Latin 'simia' ('ape, monkey') and entered English via learned formation (Latin/French influence); 'non-' as a negative prefix was attached in Modern English to create 'non-simian' to express the opposite of 'simian'.

Originally, 'simian' meant 'of or pertaining to apes or monkeys'; 'non-simian' developed later as a straightforward negative formation to mean 'not simian' without major semantic shift.