Comparative form of yellow: more yellow(adjective)
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Use "yellower" in a sentence
"Between the three phones, there's a noticeable difference in display color temperature, much like we saw with the iPhone and iPhone 3G -- the Storm and Curve have a noticeably "yellower" hue than the Bold."
"Whenever I returned to the store the pages of what remained had grown yellower probably along with me until they vanished completely."
"And, yeah, I had to work in the morning, but hearing you exasperate with the subtle lectures on yellower teeth and chimney kisses was worth the oncoming exhaustion."