nonchalantness Share definition Flag Is someone who cares about another person but doesn't want to show that they care. He would have to give some of his nonchalantness up and meet me in the middle to make the relationship work. nonchalantness by Gusto66 February 3, 2021 0 0 Get merch Get the nonchalantness mug. Buy Now — $32.95 See more merch