Ist ihnen schlecht?=Are you bad(badis a feeling)/Do you feel bad? Ihnen is a polite form.

@Drekir: your example "ist ihnen schlecht" means "are they feeling bad/ill" If you had written "ist Ihnen schlecht" it would have meant "Are you feeling bad/ill". The only difference is the capital in Ihnen (you). Anyway: keep in mind that it is an impersonal construction with the verb in singular. More examples: mir ist kalt, mir ist warm, mir ist übel (move away, he is going to throw up!!)

Well i know, but ihnen (not Ihnen) always takes plural conjugation. I want to ask about the verb conjugation.. as sie (plural) or Sie (sing/plu) always take plural conjugation form..

I think Drekir's question is about why the sein has been conjugated in the third person singular (er/sie/es ist ) rather than in the third person plural ( sie sind ). The answer I guess has to do with the German equivalent of the English impersonal 'it'. In other words, "Is (it) bad for them."

Ok yes found the answer on google... Yes Talat you are right.. It is actually "Is (it) bad for them". I was confused because of "Sind sie schlecht?" which is the same, but lit. translates as "are they ill", instead of "Is (it) bad for them". Thnx guys..