불호령 means an order to you that is used to scold you very strictly to make you not do something. <Example> Mom: You! Come on! Look at the floor! I said to clean your room! Child: I'm sorry. Mom: How many times should I say to you? It's because you were playing a game every time! Child: I'm so sorry, mom... Mom: Do not play the game anymore. If you break it, then I'll really break all of your games and phone. Do you understand? Child: ... (on the verge of crying) Mom: (shouting) Give me a sign! Do you understand me? Huh? This situation is an example when the mother uses 불호령 to her child. Hope it helps. :)

So here, the implication I believe is that he is about to make a scene. Complain with yelling, loud voice, scolding, etc.