The Incite Greed spell's duration can be ended by my companions doing anything harmful to the afflicted targets. What is considered harmful for the purpose of the spell's duration?
until the spell ends, or until you or your companions do anything harmful to it.
In many places, the harm is defined when introduced as a term (see for examples: PHB 109; PHB 118; PHB 259). The harm here seems to be undefined, did I miss the definition here or on another page of the book?