Trashtise is derived from 2 words: trash and chastise
: a disreputable person
: to punish, to scold sharply
Definition of trashtise: to sharply scold a disreputable person.
The difference between chastise & trashtise is that the recipient is disreputable.
One would properly use trashtise when they wanted or needed to drive home a point in a very strong manner.
Trashtised is only used in reference to a verbal beating and must NEVER refer to any physical altercation. This is in an effort to promote a kinder, gentler planet.