Dictionary / Vocabulary / 欠く
かく
to chip; to nick; to break; to crack
JLPT N1 common word Also written 闕く
本書の欠点は、既婚者である著者が非婚をすすめても、説得力を欠く事である。
The weak point of this book is that it's less than persuasive when the married author recommends not being married.
恩人に礼節を欠いてはなりませんよ。
You must not lack decorum dealing with your benefactors.
彼は人間としての感情を欠いていた。
He was devoid of human feeling.