Definition of adultoid in English:
adultoid
noun ˈadʌltɔɪdəˈdʌltɔɪd
Entomology An insect that has many features of an adult form but is not a typical imago.
adjective ˈadʌltɔɪdəˈdʌltɔɪd
Entomology Designating or characteristic of such an insect.
Origin
1940s. From adult + -oid.