That would be: الربيع ممطر
We remove the (AL), the definite article, from the adjective. By doing this, we release the adjective from the grip of the noun, and thus the adjective does not follow the noun, and not becoming an attributive adjective for (the spring), but rather it is now a predicative adjective that tells the status of (the spring).
Attributive adjective in Arabic follow the noun they describe in everything: Gender, Number, and Definition.
Predicative adjective, on the other hand, which require the verb (to be) in English and most (Western) European languages, follow the noun in Arabic as well, in gender and number, BUT NOT the definition.
- The rainy spring: الربيع الممطر
- The spring is rainy: الربيع ممطر
Some reasons... but mainly the time i have
I, also, don't see myself as the proper person to contribute and design a course. Such things would (and should) be prepared by a true language teacher which honestly, to what I see, is not done here. I have a hunch that contributors for this course of Arabic are mainly amateurs and not linguists - and despite me explaining some aspects of the language, I am really no language teacher nor a linguist, but rather an amateur as well.
If this course is to get any better, people with REAL language certificates and teaching experience must be the contributors.
To what I see, this course is like a traveler's Arabic as I call it; Something to get you through.
On the other hand, many people really seek dialects rather than MSA (and they have a point in that for practicality reasons for every day usage).