defect

(noun): A fault or malfunction.
(noun): The quantity or amount by which anything falls short.
(noun): A part by which a figure or quantity is wanting or deficient.
(verb): To abandon or turn against; to cease or change one's loyalty, especially from a military organisation or political party.
(verb): To desert one's army, to flee from combat.
(verb): To join the enemy army.
(verb): To flee one's country and seek asylum.

a defect in the ear or eye; a defect in timber or iron; a defect of memory or judgment