When we define terms, we carry at least two responsibilities. First, to the thing named by the word, and second to the person spoken to.
It might make sense to expand that second responsibility to the whole community of people who use the language. Definitions have the power to shed light and thus heal, or to shed confusion and thus dis-ease.
The notion that I have the right to make a word mean what I want it to mean, to disregard the whole tradition that gave us the word and its meaning and the whole current use of the word, is rooted in arrogance and undercuts relationships.