There are numerous synonyms for describing an underhanded or unreliable person. These include "deceitful," "untrustworthy," "treacherous," "scheming," "dishonest," "shifty," "dodgy," "conniving," "manipulative," "backstabbing," "two-faced," "duplicitous," "disloyal," "double-dealing," "fickle," "unscrupulous," "unreliable," and "devious." Each of these descriptors highlights a different aspect of an individual who cannot be trusted or who operates with ulterior motives. Whether in personal, professional or political settings, identifying and avoiding these types of individuals is crucial for maintaining integrity and building trusting relationships.