Comparative form of skinny: more skinny(adjective)
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Use "skinnier" in a sentence
"Anyway you know who thinks skinnier is more attractive?"
"She's freakin skinnier than Sporty Spice, the skinniest of the 5!"
"i grew up listening to young michael jackson, we're only a few years apart--i used to imitate him so exactly i could have been donny osmond. now michael looks like me, only much skinnier, which is terrifying. i never, ever, ever wanted that to happen."