The crossword solution for the term 'SOURCE OF A LEAK, PERHAPS' is MOLE. A MOLE is a small burrowing mammal that lives underground and is known for its digging ability. In this context, a MOLE can also refer to a person who secretly passes information to another party, often without the knowledge of their employer. This type of MOLE can be a source of a leak, as they are able to provide confidential information to an outside source.