Change 1 letter to make a new word #2

Park

Peck

sick

click

Cleck

Clark

Flerk 

(An English word that became obsolete after 1653. It means jerk. It was used both as a noun and verb)

 coco_2521:

Glerk : A person who wastes time

Did we hit the wall just now?

If so, I suggest bleak as the new word