Maybe “osé” or “risqué”. These 2 words are not too specific, but they do mean that something risqué is going on. “Osé” would be more common nowadays, and it is quite concise. “risqué” has been stolen by the English language.

Example:

Tu as vu ce qu’elle porte? C’est vraiment osé!

Now that I think about, maybe “risqué” is no longer in use in French with the sense of “osé”. Interesting chassé-croisé between French and English.

"Osé", as Frank suggested, is very good. Other possibilities would be "affriolant" or "aguichant":

Elle porte toujours des vêtements affriolants.

Elle porte toujours des vêtements aguichants.

Both of these words that are almost excusively used for describing such clothing:

• "Affriolant" leaves a more positive impression (describes clothing used to seduce, without the vulgar connotation). It is also used more often for underwear clothing.
• "Aguichant" clearly has a more vulgar connotation, and could be applied for any clothing.

There are also some very common expressions that carry the meaning you want, although they don’t use a specific word:

Elle portait une tenue qui montrait tout. (more colloquial)

Elle portait une tenue très déshabillée. (more used for nicer clothings, like evening dresses)