"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.).
权威例句
1. Will Gumshoe Goose arrest the kidnapper?
私家鹅侦探能逮补真凶 吗 ?
2. Awn teaches the Wu Xu of Chinese gumshoe institute this year 74 years old.