Comparative form of blonde: more blonde(adjective)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "blonder" in a sentence
"One tall and broad, one slim and wiry and one slighter, blonder and more lost than a child."
"Heavier, and shorter, and blonder, and no longer shaving my head, and 16 tattoos, and pierced nipples, and green eyes that change to hazel and blue, depending, and glasses."
"River was completely different to all his siblings – blonder, cute and pixyish."