дурӯғ

Ин гап рост аст ё дурӯғ?
Is this the truth or a lie?
Иблис падари дурӯғ аст.
Satan is the father of lies.

Bonus:
In the first sentence гап means “talk” or “word”. The sentence could be translated as “Is what you are saying the truth or a lie?” or “Is this gossip (talk) that I am hearing true or a lie?” depending on the context.

дурӯғ гуфтан: to lie
дурӯғгӯ(й), дурӯғбоф: liar
дурӯғгӯӣ: lying

Saying: Умри дурӯғ кутоҳ аст. (The lifetime of a lie is short.)