A person who, when reading text on a computer screen, cannot help but constantly select, deselect, and reselect the text.
This highlighting ranges from constantly clicking the text at random, highlighting the words as they are read, or highlighting the words as a bookmark to stay on track.
Jimmy is a compulsive highlighter; he constantly clicks at his computer screen even while he's just reading!
A Twenty-Highlighter Girl is usually a girl named Zoey who gets As and takes a gagillion notes. Usually, a Twenty Highlughter girl is a bitch who snitches on John when he tries taking Mrs. Thompson's spot as a teacher and then won't allow Andrew into Class because she's so special;
Dave: Did you hear about how Zoe is a Twenty Highlighter Girl Jym: yeah I heard she snitched on John and wouldn't allowAndrew into the Class
The Highlighter is a sex act in which the male, while on top, pulls out, and when he finishes leaves some of his seed in the female's hair, thereby giving her highlights.
This act is best performed when the male is drunk enough to just sit there and laugh while the female freaks out.
Additional bonus if after The Highlighter is performed, the female returns for a second round of sex.
"I pulled out and completely painted this girl with cum. I even got some in her hair and gave her some highlights."
-"Did you pull the Highlighter?"
-"Yea, but she was still back in 20 seconds to get fucked again."