Plainly
look up a word, understand it — no rabbit hole
deficiency
noundih-FISH-en-see
meaning in plain English
A lack of something needed or expected, so things aren’t as full or complete as they should be.
for example
After the storm, the town had a deficiency of clean drinking water because the pipes were broken.
If you’re missing a key piece in a puzzle, you’ve got a deficiency that keeps the whole picture from making sense. Why does a missing screw in a chair matter? Because without it, the chair has a deficiency that makes it wobble and feel unsafe.