[de.fect] n [ME, fr. MF, fr. L defectus lack, fr. deficere to desert, fail, fr. de- + facere to do--more at do] (15c) 1 a: an imperfection that impairs worth or utility: shortcoming "the grave ~s in our foreign policy" b: an imperfection (as a vacancy or a foreign atom) in a crystal lattice
2. [L defectus]: a lack of something necessary for completeness, adequacy, or perfection: deficiency "a hearing ~"
[2]de.fect vi [L defectus, pp. of deficere] (1596) 1: to forsake one cause, party, or nation for another often because of a change in ideology
2: to leave one situation (as a job) often to go over to a rival "the reporter ~ed to another network" -- de.fec.tor n