What do you call a highlighter that thinks it's important?

A bit of a stand-out.

Did You Know?

"Stand-out" means both someone who's exceptional and literally standing out visually — exactly what highlighters do! The modern highlighter was invented in 1963 by Dr. Frank Honn at Carter's Ink Company, who created a fluorescent ink that wouldn't smudge or bleed through paper. Yellow became the most popular color because it's bright enough to catch attention but doesn't interfere with reading black text.