pejoration

価値下落、(語義の)悪化

(noun) The process or condition of worsening or degenerating.
(noun) Linguistics The process by which the meaning of a word becomes negative or less elevated over a period of time, as silly, which formerly meant "deserving sympathy, helpless or simple,” has come to mean "showing a lack of good sense, frivolous.”

Crafty once meant powerful, and cunning meant knowledgeable; each has gradually taken on negative connotations (this is called pejoration).

impair

悪くする、害する、傷つける ◇L.in(＝強意)＋pejorare(＝より悪くする)

損傷、障害、棄損

価値を下げる、(語などが)軽蔑的な ◇L.pejorare(＝いっそう悪くする)