The author of the Feature Service can apply Definition Queries to a layer before they share it as a feature service but once published there is currently no way to perform a filter on an existing feature service accept by rectangular service limit. What is the type of Def Query you'd like to perform to accomplish what task? There may be other suggestions I might have for you depending on what you are trying to do.
Hi Don! Thanks for responding. We are trying to allow users to view and edit a feature service in AutoCAD, however we only want to bring in a subset of the feature service, as the whole thing takes way too long to load. We don't want to have to publish a different feature service for each selection set that we'd like to show a user in AutoCAD. Each user is only going to be interested in viewing or editing the data specific to their project. Thanks ahead of time!