Lewis & Short

mītesco (mitisco), ĕre, v. inch. n. [mitis], to become mild or mellow, to grow ripe (of fruits, to lose their roughness or harsh flavor; class.).

  1. I. Lit.: nec grandiri frugum fetum posse nec mitescere, Pac. ap. Non. 343, 16 (Trag. Rel. v. 142 Rib.): uvae a sole mitescunt, Cic. Oecon. ap. Gell. 15, 5, 8: mala, Plin. 15, 14, 15, § 51: cornus, arbutus, prunus, piri, to grow mellow, ripe, Col. 7, 9: sunt (herbae) quae mitescere flamma, Mollirique queant, Ov. M. 15, 78: ervum, Plin. 22, 25, 73, § 153.
    1. B. Transf., in gen., to grow mild, soft; to grow gentle, tame: offirmatod animo mitescit metus, Pac. ap. Non. 406, 9 (Trag. Rel. v. 293 Rib.): nullum est ingenium tantum neque cor tam ferum, quod non … mitiscat malo, Att. ap. Non. 473, 6 (Trag. Rel. v. 684 Rib.): caelum mitescere, arbores frondescere, Poët. ap. Cic. Tusc. 1, 28, 69: hiems, Liv. 23, 19: annus, Sil. 15, 505: frigora, Hor. C. 4, 7, 9: Alpium juga, Plin. 3, 25, 28, § 147: ferae quaedam numquam mitescunt, Liv. 33, 45.
  2. II. Trop., to grow mild, gentle: nemo adeo ferus est, ut non mitescere possit, Hor. Ep. 1, 1, 39.