It is a rastafarian man who is also an abortionist. Popularised in one of petercoffin's (YouTube) parody of the film Twilight: New Moon.
There is no specific definition for "rastabortionist." It appears to be a made-up term that combines elements of Rastafarianism and abortion. Rastafarianism is a religious and cultural movement that originated in Jamaica, while abortion refers to the termination of a pregnancy.