- gumshoe (n.)
[gumshoe 词源字典]
- "plainclothes detective," 1906, from the rubber-soled shoes they wore (allowing stealthy movement), which were so called from 1863 (gums "rubber shoes" is attested by 1859); from gum (n.1) + shoe (n.).[gumshoe etymology, gumshoe origin, 英语词源]