Grown-up and Grownup

Grown-up adjective - Relating to or typical of adults; displaying proper maturity.

Grownup and grown-up are semantically related In some cases you can replace term "Grownup" with "Grown-up", this terms are similar.

Grownup adjective - (of animals) fully developed.

Grown-up and grownup are semantically related in developed topic. You can use "Grown-up" instead the word "Grownup" as an adjective or a noun, if it concerns topics such as grown, experienced, fully grown, nubile.