From Longman Dictionary of Contemporary Englishkeep the wolf from the doorkeep the wolf from the doorSURVIVEto earn just enough money to buy the basic things you need I work part-time in a coffee shop just to keep the wolf from the door. → wolf
Examples from the Corpus
keep the wolf from the door• But it was worth it to keep the wolves from the door.• No sign of any more money than is needed to keep the wolf from the door. 