deficiency (n.)

1630s, "state of falling short, a lack or failing;" 1660s, "that in which a person or thing is deficient, inadequacy," from Late Latin deficientia, from deficient-, present-participle stem of deficere "to desert, revolt, fail," from de "down, away" (see de-) + combining form of facere "to do, make" (from PIE root *dhe- "to set, put"). The older English word, now rare or obsolete, was deficience (mid-15c.).