In Act 1, scene 3, the first witch tells a story about how she approached a sailor's wife who was busily eating chestnuts. She demanded that the woman hand some of her snacks over, and the sailor's wife basically told the first witch to get lost. We can tell, then, that the first witch is not happy with this woman to begin with because she issued a direct order to the woman and the woman told her to go away. Thus, the first witch is denied snacks and treated disrespectfully. The first witch, therefore, calls the sailor's wife a "rump-fed runnion" (1.3.7). The word "rump" does not have a particularly positive connotation, and certainly not in the context of being eaten. To be called "rump-fed" sounds like an insult, and so "runnion" likely follows connotative suit.

Further, a few lines later, the first witch says that she plans to sail to Aleppo, where the woman's husband has gone, and she is going to torture him by preventing him from being able to sleep. She says that she will "drain him dry as hay" and that "He shall live a man forbid[den]" to sleep (1.3.19, 1.3.23). If she were pleased with his wife and his wife's behavior, the first witch would really have no cause to go so far to torture a stranger. This also helps us to understand how the first witch feels about the sailor's wife and to infer that "runnion"— though unfamiliar—is not a compliment.