'assyrianize' originates from Modern English, formed from 'Assyrian' + the suffix '-ize', where '-ize' came via Greek '-izein' through Latin/French and meant 'to make or become'.

'Assyrian' itself comes from Latin 'Assyrianus' and Greek 'Assyrios', ultimately from Akkadian 'Aššur' (the name of the city/god). The modern English verb was created by adding the productive English suffix '-ize' to 'Assyrian'.

Initially related specifically to the place or people ('Assyrian'); with the verb formation it came to mean 'to make or render something Assyrian' (i.e., to convert/adapt to Assyrian form).