De‐fi″cien‐cy (?), n.; pl.Deficiencies (#). [See Deficient.] The state of being deficient; inadequacy; want; failure; imperfection; shortcoming; defect. “A deficiency of blood.” Arbuthnot.
was so miserably ignorant, that his deficiencies made him the ridicule of his contemporaries. Buckle.
Deficiency of a curve(Geom.), the amount by which the number of double points on a curve is short of the maximum for curves of the same degree.