adjective
Definition: Relating to the process of forming or developing something, especially in its early stages.
Example: The formative years of a child's life are crucial for their development.
noun
Definition: A part of a word that helps to create its form, often as a prefix or suffix, and is not part of the main meaning of the word.
Example: In the word 'unhappiness', 'un-' is a formative that changes the meaning of 'happy'.