'non-mystical' is formed in English from the prefix 'non-' and the adjective 'mystical'. 'Non-' ultimately comes from Latin 'non' meaning 'not', and 'mystical' comes via Late Latin 'mysticus' and Old French 'mystique' from Greek 'mustikos' related to 'mysterion' meaning 'secret'.

'mystical' developed from Greek mustikos (relating to mystery/secret rites) into Latin mysticus, then Old French mystique, and into Middle/Modern English as 'mystical'. The negative prefix 'non-' was borrowed from Latin and used productively in Middle and Modern English to form negated adjectives like 'non-mystical'.

Originally 'mystical' meant 'relating to mysteries or secret religious rites'; over time it shifted toward 'spiritual' or 'beyond ordinary understanding'. 'Non-mystical' therefore denotes the absence of those qualities — i.e., ordinary, natural, or explicable.