Real, or perceived, workplace bullying exhibited by a supervisor against a subordinate may condition a subordinate to withhold disagreement, or communication of contrarian information, from the supervisor. Existing research and literature demonstrate the mum effect and its influence on communicators given generally neutral associations with message recipients. The mum effect is the tendency for communicators to feel a sense of guilt and association with bad news delivered to a message recipient. Given an alternative, communicators prefer to remain mum than to deliver the bad news. However, research of the mum effect has minimally explored divergent conditions. Through an exploration of workplace bullying, whistleblowing, and existing literature regarding the mum effect, the author presents a divergent theme to the hierarchical mum effect which the author labels the tyrannical mum effect. The tyrannical mum effect is established under the framework of seven propositions which provide the foundation by which a supervisor exhibits workplace hostility to subordinates, subordinate interpretation of the hostility, and the willingness of the subordinate to communicate disagreement in a hostile work environment. The seven propositions of the tyrannical mum effect provide opportunity for future research.