To take, steal, or pilfer something seen as unused, under the thief's belief they will make good use of it. Thought of as a euphemism to avoid guilt by believing the victim will not miss the item (or, if discovered, appreciate the act's necessity).
"He has a whole box of Pop Tarts, there's no harm if we necessitake a few."
"Who necessitook the flash drive that was on the counter? I need it back, please..."