I am looking for a word or words that would descibe non verbal slander

What word would best describe the act of slowly making someone to be looked poorly upon?
In a sense slander, but to be able to do it without verbaly saying/speaking the slander?

For example suppose a person named Jake Hitler frequently implied that his neighbor St. Francis
had horrible breath. Jake would never utter the words "Bad breath" to anyone, but whenever he
could in social situations, he would in various ways imply that St. Francis's breath
was horrible? Jake Hitler would carry this out cleverly for months, and do it so well that other
neigbors began to believe that St. Francis had horrible breath. (Even though he St. Francis had breath smelled
very good?) And so even thought Jake Hitler never uttered the words "Bad breath" he effectively
convinced 98% of the people that St. Francis had bad breath.

I believe the word "Character assasination" would be too strong. Perhaps someone could offer a word
of series of words that could best describe what I am talking about?