Substitute most appropriate word for following from the given options:
That which cannot be satisfied

insatiable

The most appropriate word for that which cannot be satisfied is insatiable.

• Leonine means having the qualities of a lion, such as courage or strength.
• Indelible means impossible to remove or erase.
• Insatiable means impossible to satisfy.
• Unfathomable means too deep or obscure to be understood.