(of a spirit) containing less than 57.1 per cent alcohol by volume
underproof in American English
(ˌʌndərˈpruf)
adjective
containing less alcohol than proof spirit does
underproof in American English
(ˈundərˈpruːf)
adjective
containing a smaller proportion of alcohol than proof spirit
Word origin
[1855–60; under- + proof]This word is first recorded in the period 1855–60. Other words that entered Englishat around the same time include: barrage, kickoff, lavabo, pipeline, specialistunder- is a prefixal use of under, as to indicate place or situation below or beneath (underbrush; undertow); lower in grade or dignity (undersheriff; understudy); of lesser degree, extent, or amount (undersized); or insufficiency (underfeed)