A person who is trying to become slim by dieting.(noun)
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Use "slimmer" in a sentence
"And there is clearly a bigger discussion to be had about how newspapers can continue to thrive as readers increasingly move to the Web, where the profit opportunities remain slimmer than those in print."
"There are several fad diets that will allow you to take off 10 pounds in just 7 to 10 days Be aware, however that this weight loss does not translate to a long-term slimmer you as much of what you lose is water weight However, if you have a big event coming up shortly, you may just want to lose pounds in a week"
"While you're at it, did anyone ask fire and police how they like the idea of slimmer roads in residential neighborhoods?"