Lack
Deficiency
noun, する verb
You lack likeness to anything out there. You totally lack something that gives you likeness. It's a deficiency, or something.
けつじょ
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
ビタミンB1が欠如すると、脚気になるかもしれないですよ。
A Vitamin B1 deficiency might cause beriberi.