Wiktionary
harshen
vb. 1 To make, or to become harsh; render hard and rough. 2 To render peevish, morose, or austere.
WordNet
harshen
v. make harsh or harsher; "Winter harshened the look of the city"
Usage examples of "harshen".
My chest tightened, my breath harshened, my feet blistered with the agony of the dance, my breasts and belly burned with the liquid tempo of my body.