[UNDER-1 4 a, b. Cf. OE. underflówan.]
1. intr. To flow beneath.
1610. Holland, Camdens Brit., II. 45. It looketh downe to the underflowing sea.
1647. Hexham, I.
2. trans. To flow in under (something).
1872. Dixon, Switzers, v. 45. The waters underflowed the beams, and lifted the strong habitations.