noun
rattrap; mousetrap
A trap for catching rats or mice. The word is a straightforward compound of 鼠 (rat/mouse) and 落とし (trap).
倉庫に鼠落しを仕掛けた。
I set a rattrap in the warehouse.
罠 is a general term for any trap or snare, while 鼠落し specifically refers to a trap for rats or mice.
Compound of 鼠 (nezumi, 'rat/mouse') and 落とし (otoshi, 'trap'), literally 'rat/mouse trap'.