1. a substance used to fill cracks, holes, or gaps in a surface
2. something used to occupy space or time, especially when of lesser importance
3. a person or thing that fills a position temporarily

Examples

• He used wood filler to repair the scratches on the table.
• The magazine included several filler articles to reach the required page count.
• She worked as a filler until they found a permanent replacement.
• The sausages contained cheap filler ingredients like breadcrumbs.
• Apply the wall filler with a putty knife and let it dry completely.
• The radio station played music as filler between news segments.
• Many processed foods use corn starch as a filler.