postmature
/ˌpəʊs(t)məˈtʃʊə/ /ˌpəʊs(t)məˈtjʊə/adjective
1 Obstetrics. Of an infant: born after a pregnancy lasting significantly longer than normal; post-term. Of labour or birth: occurring after such a pregnancy.
2Relating to or designating a person or animal over the age of maturity; (Biology ) relating to or designating an organism, cell, or other structure undergoing development which has passed the age or point of maturity.
Origin
Late 19th century. From post- + mature, after premature.