decaffeinate

verb (used with object), de·caf·fein·at·ed, de·caf·fein·at·ing.

1. to extract caffeine from: to decaffeinate coffee.

verb

1. (tr) to remove all or part of the caffeine from (coffee, tea, etc)

v.

1909 (implied in decaffeinated), from de- + caffeine + -ate (2).