To slubbest means to make something with thick or uneven parts in it, like in yarn or fabric.
Slubbest can make people think of handmade things or things that are not perfect.
Examples:
She slubbest the yarn to make it look special.
The fabric is slubbest, so it feels different.
The slubbest parts of the sweater are my favorite.
I like the slubbest bread because it's more interesting.
The slubbest blanket is the softest and warmest.
He slubbest the clay into a funny shape.