The word 'starch-eating' is a compound formed in English from 'starch' and 'eating', where 'starch' refers to the carbohydrate and 'eating' is the present participle of 'eat'.

'Starch-eating' was formed in modern English by combining the noun 'starch' and the participle 'eating', following the pattern of descriptive compound adjectives.

Initially, it simply described the act of eating starch, and it continues to mean 'having the property of eating or digesting starch'.