"Who knows the famous lawyer?"
Translation:Ki ismeri a híres ügyvédet?
No, tud is for knowing a fact, or knowing how to do a thing ("can" or "be able to" do something). Ismer is for "being acquainted with" people (or places or other things).
That's definite conjugation, because the direct object in this sentence, the lawyer, is a definite object, marked with a. A single certain lawyer. Definite conjugation uses a separate set of conjugational suffixes.