A film that teaches socially acceptable behavior. Here in America, morality films were used extensivly in the 1940's and 50's to teach people primarily about unamerican activity and safety; drug use, Communism, how to survive a nuclear attack etc. One of the most well known morality films is Reefer Madness (Know Your Dope Fiend!).
They've also been known to dictate (as opposed to teach) various stuff about sexuality and other related stuff here in the USA. How to behave on a first date, and how to tell that evil unamerican homosexuals are hitting on you, are additionaly some subjects of found in these pieces of cinematography.
I wonder what morality films are used for in other countries (Thinking about Marxist type related stuff)