Learn Arabic (Modern Standard): غير معقول! نجحت في الامتحان؟

غير is used directly before adjectives or nouns to mean "un-", "non-", or "in-". Unlike ليس (which negates whole nominal sentences) or لا (which mostly negates verbs), غير creates a direct opposite of the specific word that follows it. Here, it turns معقول (believable) into غير معقول (unbelievable).

What is the root of معقول and what does it literally mean?

It comes from the root ع-ق-ل which is related to the mind, intellect, or reason. معقول is a passive participle (a word pattern showing the receiver of an action) that literally means "reasonable" or "comprehensible".

Why is the preposition في used after نجحت? Doesn't the English translation just say "passed the exam"?

This is a classic difference between English and Arabic! The Arabic verb نجح actually means "to succeed". So instead of "passing" an exam directly, in Arabic you "succeed in" it. You must always use في with this verb when talking about tests, classes, or life goals.

Can we ask a question in MSA without using a question word like هل?

Yes. Even though formal MSA usually starts yes/no questions with هل or أ, dropping them is perfectly fine in exclamations of surprise. Just like the English "You passed the exam?", the punctuation and your tone of voice do all the work here to express shock.