Other forms: deficiencies
A deficiency is a shortage of something needed, or a weakness in something. Not enough, and it shows.
Medicine uses it precisely, and a vitamin D deficiency or an iron deficiency is a diagnosis with a treatment. The other sense is about faults, so deficiencies in the system is the polite official phrase for things that went badly wrong. It takes in or of. The adjective deficient takes in, as in deficient in calcium, and the word is more formal than lack.
1noundeficiencyA shortage of something essential.
“Tests showed a serious iron deficiency.”
2nounfaultA fault or weakness in something.
“The report listed deficiencies in the training.”
Proto-Indo-European
*dʰeh₁-
Latin
deficiens
English
deficient
English, today
deficiency
Built from
From deficient + -cy. Compare Latin dēficientia. deficient comes from Latin deficiens, present participle of deficere (“to lack, fail, be wanting”); see defect.
Etymology from Wiktionary, CC BY-SA