Slubbings are thick, uneven parts in yarn or fabric.
Slubbings can make the yarn or fabric look interesting and unique.
Examples:
The sweater had slubbings in the yarn.
The slubbings in the fabric gave it a rough texture.
I like the slubbings in this scarf.
The slubbings in the blanket made it look bumpy.
The slubbings in the rug were big and lumpy.
The slubbings in the shirt made it feel rough.