Definition of 下_しも

noun:

• lower reaches (of a river) Antonym: 上【かみ】
• bottom; lower part
• lower half (of the body, esp. the privates); feces (faeces); urine; menses
• end; far from the imperial palace (i.e. far from Kyoto, esp. of western Japan)

~の noun:

• dirty (e.g. dirty jokes, etc.)