What is the difference between a fault (عيب) and what is forbidden (حرام), and is every fault forbidden, or is everything forbidden a fault?

"Impermissible" (عيب - 'ayb) is a broader concept than "forbidden" (حرام - haram). "Impermissible" can be a matter of taste or related to a specific time and place. "Forbidden," however, is what is legally condemned by Islamic law, whether it be a statement or an act of the heart. "Forbidden" is also known as "prohibited," "prevented," "disobedience," "sin," and other synonyms that indicate its prohibition and the accountability for committing it.