Meaning

adjective permitting the unwanted passage of fluids or gases

adjective used informally; unable to retain urine

adjective prone to communicate confidential information

originLikely a normalisation ( + -y) of earlier leak, leake, leke (“leaky”, adjective), from Middle English leke (“leaky”), from Old English hlec, *lec (“having cracks or rents; leaky”), from Proto-Germanic *lekaz (“leaking; leaky”). By surface analysis, leak + -y. Cognate with Scots lek, leck (“leaky”), Saterland Frisian läk (“leaky”), Dutch lek (“leaky”), German Low German leck (“leaky”), German leck…

Etymology from Wiktionary, CC BY-SA 3.0