/ dɪˈfɪʃnsi; NAmE / noun ( pl. -ies ) deficiency (in / of sth)
1.
[ U , C ] the state of not having, or not having enough of, sth that is essential
SYN shortage :
Vitamin deficiency in the diet can cause illness.
a deficiency of Vitamin B
2.
[ C ] a fault or a weakness in sth/sb that makes it or them less successful :
deficiencies in the computer system