The two verbs kuī (亏) and qiàn (欠) both could be used to indicate having none or not enough of something, but the object that the two words takes occupies different positions:
tā zhī dào zì jǐ lǐ kuī.
He knows that he is in the wrong.
It is clear in the example above, the verb phrase “lǐ kuī (理亏)” means not reasonable enough, the object lǐ(理) should appears before the verb kuī (亏).As for qiàn(欠), it should come before the object to convey the meaning of lacking of something.
nǐ zhè yàng zuò tài qiàn kǎo lǜ le.
It's too thoughtless of you to do so..
The common usage of kuī (亏) is to express the meaning of suffering a loss, qiàn(欠) usually means owing something to somebody or something.
tā zuò shēng yì kuī le bú shǎo qián.
He lost a lot of money in business.
tā zuò shēng yì qiàn le bú shǎo qián.
He owed a lot of money in business.