One picture can hold this word: a movement that is quick, light and over in a second. A lamb skips, jumps and turns in the grass. A guard's hands sweep fast down a jacket and are gone. Both are short bursts of movement with nothing heavy about them. This is offered as a way to hold the word together, not as a claim that one meaning grew out of the other.
From the word’s history
The source in this packet traces frisk to Middle English frisk (lively, frisky), from Middle French frisque (lively, jolly, blithe), of Germanic origin and ultimately a doublet of fresh. So the oldest recorded feel of the word is liveliness. The packet does not explain how the searching use arose, and this map does not claim to.
這份資料的來源說，frisk 來自中古英語 frisk（活潑的），再往前是中古法語 frisque（活潑、輕快），源頭是日耳曼語，和 fresh 同源。所以這個字有紀錄的最早感覺就是有活力、輕快。至於搜身的用法是怎麼出現的，來源沒有說明，這裡也不做推論。
Wiktionary 'frisk' etymology as supplied in this packet (source_ref kaikki:3f6f69a190036ae4:643318368, 643313364, 643302932)
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