Word Origin & History
underO.E. under, from P.Gmc. *under- (cf. O.Fris. under, Du. onder, O.H.G. untar, Ger. unter, O.N. undir, Goth. undar), from PIE *ndhero- "lower" (cf. Skt. adhah "below;" Avestan athara- "lower;" L. infernus "lower," infra "below"). Notion of "subordination" was present in O.E. Also used in O.E. as a preposition
meaning "between, among," as still in under these circumstances, etc. (though this may be an entirely separate root; see
understand). Productive as a prefix in O.E. times, as in Ger. and Scand. Under the table is from 1921 in the sense of "very drunk," 1940s in sense of "illegal." To get something under (one's) belt is from 1954; to keep something under (one's) hat "secret" is from 1885; to have something under (one's) nose "in plain sight" is from 1548; to speak under (one's) breath "in a low voice" is attested from 1832. To be under (someone's) thumb "entirely controlled" is recorded from 1754.