Lewis & Short

subter-flŭo, ĕre, v. n., to flow beneath (post-Aug. and very rare).

  1. I. Lit.: amnis sub montes subterfluens, Vitr. 8, 2 med.: torrente subterfluente, Plin. 8, 50, 76, § 201: aquae, Sen. Q. N. 3, 30, 4, acc. to Fickert and Haase (not subinfluo).
  2. II. Trop.: eos felicitas ingrata subterfluit, Eum. Pan. Const. 15.