Student or Learner
Is there another meaning of "heavy"?
I was translating an interview with Alfred Hitchcock into Arabic, I can't understand the word clearly with its meaning that I know, which is: weighty or fleshy. He says:
Mason really doesn't act like a villain, does he?
No, I didn't make him do a dastardly thing in the whole picture. I split him into three in an effort to keep him from behaving like a heavy: there's Mason himself, who only had to nod. I gave him a rather saturnine looking secretary--there was the face of Mason. And the third man--Adam Williams--he was the brutality.
not a teacher
As the first part of your quote suggests, in this context a "heavy" is a villain in the film, particularly if the role involves violence.
See definition #29 in this link.