'starch-inactive' is a modern English compound formed from 'starch' + 'inactive', where 'starch' refers to the starchy substance derived from plants and 'inactive' means 'not active'.

The elements come from older sources: 'starch' derives from Old English 'stearc' meaning 'stiff' (from Proto-Germanic *starkaz), and 'inactive' is formed from Latin prefix 'in-' (not) + 'active' (from Latin 'activus', from 'agere' to do). The hyphenated compound 'starch-inactive' is a modern scientific formation (20th century onward) that condensed the descriptive phrase 'inactive on starch' into a single adjective.

Initially the component words meant 'stiff' (for 'starch') and 'not active' (for 'inactive'); combined in modern scientific usage they mean 'lacking activity toward starch'—a technical descriptive sense rather than the older general senses.