Wiktionary
vb. 1 (context transitive of an animal English) To consume as part of a diet 2 (context transitive idiomatic English) to get stimulus from (an external object)
Usage examples of "feed off".
Id seen part of his memory of what had happened to him at the hands of other men, men that she-who-made-him had given him to, so she could feed off his pain and fear.
That would make me sicker than finding some cute human male to feed off.
Their hunger is for emotional energy, and they seem to be able to feed off that without weakening their prey.
They feed off each other: Characters suggest themesin fact, most of the viewpoint characters in carry their own individual themesbut themes also alter characters.
The ones we know best attach themselves to our bodies and feed off us, leaving calling cards that range from uncomfortable itching to serious illnesses and in extreme cases, even death.
We all live and feed off the largesse of taxpayers in other parts of the country.