Treatable

wiktionary

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From Middle English tretable, from treten(“treat”) and Old French traitable, Anglo-Norman tretable; equivalent to treat +‎ -able.

etymonline

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treatable (adj.)

c. 1300, "amenable to reason," from Anglo-French tretable, Old French traitable, and in part from treat (v.) + -able. Of wounds, diseases, etc., "receptive to treatment," early 15c.