swine
彘 centers on swine: a pig or boar. The meaning is straightforward and refers to the animal itself.
彘 is a pictophonetic character. The top component 彑 represents a pig's head, and the lower part originally depicted the body and legs. The exact historical development is uncertain, but the character has long been associated with swine.
The top 彑 looks like a pig's snout and ears, while the lower part suggests its stout body and legs. Together they form a pig.
For テイ, imagine a pig wearing a tiny tailcoat: tail -> テイ, and the pig looks absurdly formal.