soften

Short definition from Wiktionary

Verb

1. 1
   To make something soft or softer.
2. 2
   To undermine the morale of someone (often soften up).
3. 3
   To make less harsh
4. 4
   To become soft or softer
5. 5
   To become or make (a consonant) more lenis, to lenite.
6. 6
   To palatalize.