The phrase 'contrary purpose' refers to an intention or motive that is opposite or contradictory to what is expected or planned. Some synonyms for 'contrary purpose' are 'hidden agenda', 'ulterior motive', 'secret intention', 'duplicity', 'deception', 'scheming', and 'connivance'. These words suggest a sense of hidden and calculated manipulation, where the person has an ulterior motive behind their actions. In addition to these synonyms, other related terms include 'subterfuge', 'guile', 'artifice', and 'deceit'. It is important to be aware of these words to understand when someone might have a contrary purpose that is not readily apparent on the surface.