DEFICIENTLY
Etymology
Adverb
deficiently (comparative more deficiently, superlative most deficiently)
In a deficient manner.
Source: Wiktionary
DEFICIENT
De*fi"cient, a. Etym: [L. deficiens, -entis, p. pr. of deficere to be
wanting. See Defect.]
Definition: Wanting, to make up completeness; wanting, as regards a
requirement; not sufficient; inadequate; defective; imperfect;
incomplete; lacking; as, deficient parts; deficient estate; deficient
strength; deficient in judgment.
The style was indeed deficient in ease and variety. Macaulay.
Deficient number. (Arith.) See under Abundant.
– De*fi"cient-ly, adv.
Source: Webster’s Unabridged Dictionary 1913 Edition