despise, low-life, poverty
賎 centers on looking down on something as worthless or low: despising, treating as low-life, or associating with poverty.
賎 is the modern simplified form of 賤. The older form combines 貝 (shell, money) with 戔, which likely contributed the sound and the idea of smallness or cheapness, giving the sense of something of low value.
The left side is 貝 (shell, money), and the right side 㦮 looks like a stack of small, cheap things. Picture a pile of worthless shells that everyone despises as low-life poverty.
For セン, imagine a cent (a tiny coin) being despised as worthless: cent -> セン, and the poor shell money is treated with contempt.