Sifting means to separate and remove the big parts from the small parts of something, like flour or sand, by passing it through a sieve or a screen.
Sifting is a careful and precise action. It is often used in cooking and baking to make things smooth and fine.
Examples:
I am sifting the flour for the cake.
She is sifting the sand to find the small rocks.
They are sifting the dirt to find the treasure.
We are sifting through the sand for buried treasure.
Sifting through the flour took a long time.
Stop sifting the sugar onto the floor!