The term "wheeler-dealing" is often used to describe someone who is involved in shrewd or underhanded business dealings. When looking for synonyms, one might consider phrases such as "cutthroat," "scheming," "manipulative," or even "corrupt." Alternatively, one could also use less negative terms to describe someone who is skilled at making deals, such as "savvy," "shrewd," "resourceful," or "diplomatic." Ultimately, the ideal synonym will depend on the context in which it is being used - while some situations may call for a harsher term, others may require something more neutral or positive.