The Collaborative International Dictionary
Maturescent
Maturescent \Mat`u*res"cent\, a. [L. maturescens, p. pr. of maturescere to become ripe, v. incho. from maturus. See Mature, a.] Approaching maturity.
Douglas Harper's Etymology Dictionary
maturescent
1727, "grown ripe," from Latin maturescentem (nominative maturescens), present participle of maturescere "be ripe, ripen," from maturus "ripe" (see mature (v.)) + inchoative suffix -escere.
Wiktionary
maturescent
a. Approaching maturity.