inasprire

Etymology
From.

Verb

 * 1)  to tighten up, to harshen (discipline, etc.)
 * 2)  to embitter, to sour (a relationship, etc.)
 * 3)  to become harsh
 * 4)  to become sour
 * 5)  to get stronger, to worsen
 * 6)  to wither