1. To intervene or to be involved in the activities, interests, and concerns of other people when such involvement is not wanted: Neil was accused of meddling in other people's personal lives; especially, because he meddled with things that were considered to be "none of his business".
2. To handle or to change something that is not wanted or which is harmful: Jennifer told her brother that she didn't want him to meddle with her personal things anymore!

An act of interposing or giving advice when it is not wanted: Vernon was very upset with the meddling of another college student who was telling him which courses he should take the following semester.

Pertaining to advising or telling another person what he or she should do: Brad's meddling co-worker, Janine, was suggesting procedures which he was sure could ruin his career with the company.