Best definition
Yardle is difficult to describe, as it encompasses many facets of life. To some it is a way of life,

yet to others it is simply a strange word.In its common form, it refers to a general fuckup, as in “pulling a yardle”. However, it can also refer to a general attitude of not caring too much about small problems. Sometimes, it lacks any meaning at all.

John almost broke the bong, he totally pulled a yardle.
yardle: define #2
A common greeting used when there is a language barrier
English speaking person: hello

Sweedish speaking person: ?????????

English speaking person: Yardle!

Sweedish speaking person: Ahh! Yardle!