yngja

Verb

 * 1) to make younger

Etymology
Derived from the adjective, with an i-umlaut probably introduced by analogy of other factitive verbs, such as how the verb is derived from the adjective  (both present in Old Norse as  and  respectively). Something similar appears to have happened in 🇨🇬.

Verb

 * 1)  to make younger
 * 2) to have kids, kittens, etc.