In Hollywood’s worldview, high school is a battleground where teenagers, divided into cliques, fight for supremacy, a la 2004’s “Mean Girls.”

In that spirit meet “The DUFF” (Lionsgate), a derivative comedy based on a demeaning premise: that certain students are branded the “Designated Ugly Fat Friend.”

A DUFF, as explained in the eponymous novel by Kody Keplinger, serves two purposes for the cooler, prettier girls in school: Her unfortunate appearance highlights the beauty of her so-called friends, and she also provides an approachable gateway for guys seeking a date with one of her chums.

DUFFs may be self-aware or not. In the case of down-to-earth Bianca (Mae Whitman), she’s devastated to learn the truth of the label put on her by her duo of gal pals, Jess (Skyler Samuels) and Casey (Bianca Santos).

A sympathetic teacher, Mr. Arthur (Ken Jeong), offers Bianca advice on turning the other cheek, as he himself was a DUFF many years ago. (DUFFS, it seems, span the sexes.)

Bianca sets out to erase her designation and take down the meanest girl in her high school, the queen of the labelers, Madison (Bella Thorne).

Bianca enlists the help of her neighbor, Wesley (Robbie Amell), who just happens to be Madison’s ex-boyfriend. Captain of the football team and the most popular guy in school, Wesley asks, in exchange, for Bianca’s assistance in passing chemistry.

And so Wesley becomes Henry Higgins to Bianca’s Eliza Doolittle, and the ugly duckling is transformed into a swan, of sorts. The strife rages on, and director Ari Sandel juggles a surfeit of screeching and a torrent of tears. Unfortunately, along with lax underlying values, vulgar sex talk and expletives abound, obscuring some positive messages for young people about self-esteem and respecting the dignity of others.

The film contains a benign view of nonmarital sex, frequent sexual images and references, underage drinking and occasional profane and crude language. (A-III, PG-13).