The phrase "hadst dealings" can be defined as having had interaction or association with someone or something. Some possible synonyms for this phrase include: had dealings with, interacted with, engaged with, communicated with, collaborated with, worked with, partnered with, associated with, encountered, and engaged. These words all convey the sense of having had some form of relationship or connection, whether positive or negative. Other related concepts include networking, socializing, negotiating, and liaising. Overall, the phrase "hadst dealings" is a common way to describe any type of past interaction or relationship with another person or entity.