Learn English – Making new verbs from the given words

The girl who love(s) kittens.

The construction is called a relative clause, and "who" here is a relative pronoun.

If the clause is in the present tense, and has a third-person singular subject, then yes, the verb should have the suffix (e)s.

Wikipedia says the clause also should be in the Indicative Mood.

Note that this only works for third-person subjects:

You, who love kittens, come here and see a new kitten clip I've just found on YouTube! (a bit high-hat, but anyway: the second-person you licenses the use of love, not loves)
We, who love kittens, gather in this quiet park every Saturday. (first-person subject we --> love, not loves)

An example from a poem: the poet addresses the Moon (second-person: you) and thus uses rise, not rises in the relative clause starting with the relative pronoun "that":

Enormous moon, that rise behind these hills
Heavy and yellow in a sky unstarred
And pale, your girth by purple fillets barred
Of drifting cloud, that as the cool sky fills
With planets and the brighter stars, distills
To thinnest vapor and floats valley-ward,—
You flood with radiance all this cluttered yard,
The sagging fence, the chipping window sills.

The author of one poetic blog explains this in this way:

Interesting that she uses "rise" for the moon in line 1 and not "rises." I think she is addressing the moon—"you that rise."

At the same time, she uses "sky fills" and "cloud ... distills". (these are third-person subjects)

Reference:

• English Verbs: third person singular present - Wikipedia
• Some interesing bits on the history of verbal suffixes - ELU

Yes, a common word for that is revealing as in revealing clothes. The idea here is that it reveals more about a woman than it should be. Another good one and equally common is skimpy as in skimpy skirt. So, you could say:

The clothes worn by western women could be considered too revealing in Muslim countries.

As for the adjective to describe a woman who wears revealing clothes, I don't think there is a special term for that in English that's common enough that you'll ever hear it used, but the closest thing that I can think of would be floozy. floozy is basically a slur for a woman who looks like a prostitute.

PS: people have been giving a lot of feedback in the comments section. Some of them aren't fond of the idea that what has been offered so far has mostly been vulgar slang. If you're looking for a term that's non-derogatory and neutral in language, immodest woman or immodestly dressed woman could be your best bet. This adjective was suggested by Nigel Touch (in the comments section).

Considering the new information you provided us with, all I can say is that what we are really dealing with here is terminology specific to a particular field in a foreign language. The typical way to go about this is to use the word as it appears in the original language but in its transliterated form with a remark about its meaning when the word is first introduced to the audience. This is commonly done for words that don't have equivalents in the English language. That's actually one way new vocabulary is created. There are many examples of Arabic words in English that have entered the language for the exact same reason—they have no English counterparts. Among them are terms like dunya, iman, fatwat, tawhid and many more others. Simply put, when speaking in the context of Islam, those are the words you would be using instead of analogous English ones that might be similar in meaning but don't quite capture the idea accurately.