A particular weight class, or member of such, as prescribed by the rules, between that of the heavier welterweight and the lighter featherweight. See Wikipedia for the specifics of each sport.
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Hobbies, Lifestyle, Rowing, Sports A particular weight category as prescribed by the rules, separate from an open or heavyweight class.
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Hobbies, Lifestyle, Sports, Weightlifting A competitive weight division as prescribed by the rules, between the heavier middleweight and the lighter featherweight.
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One of little consequence or ability.
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A person who cannot handle their drink; one who gets drunk on very little alcohol.
"Wait, is this about the other night when you two lightweights totally went on that bender?"2005 August 23, Haley Hazelton, Misfile (webcomic), 2005-08-23:
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Broadly A person with low endurance.
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A political candidate with little chance of winning.
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Something that is light in weight, or relatively so.
He mentions the "huge engine, lying on its side"—it was in fact a 2-2-2 weighing but 27 tons, something of a lightweight, even for 1868.1958 May 23, Rev. A. W. V. Mace, “North Wales and the "Irish Mail"”, in Railway Magazine, page 309:
lightweight
adj
US /laɪtˈweɪt/
Etymology From light (“not heavy”, adjective) + weight (noun).
1
Lacking in earnestness, ability, or profundity.
2
Having less than average weight.
[…] the Plan incorporates in proper combination every available modern technique, including extensive electrification on the new standard high-voltage a.c. system at a frequency of 50 cycles; main-line diesel traction as a half-way house to electrification; lightweight diesel trains for secondary and branch services; and a smaller wagon fleet doing more work by the use of continuous brakes in conjunction with modernised terminals and marshalling yards.1958 January 23, 'Borderer', “Ten Years of British Railways”, in Railway Magazine, page 15:
For example, lightweight construction and Jacobs bogies save weight, and a lighter train uses less power.2021 May 19, David Clough, “Swiss precision meets UK growth”, in RAIL, number 931, page 57:
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Speaking of round sunglasses, these lightweight polarized ones and come in two shades of tortoiseshell as well as black and bronze.2023 June 26, Lauren Caruso and Jillian Tracy, “The 22 best sunglasses for summer, according to style experts”, in CNN, archived from the original on 14 Apr 2025:
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Lacking in strength.
With the Gunners far too lightweight in midfield, Mikel Arteta dropped back into a deeper-lying role. This freed Yossi Benayoun to go further forward, a move that helped forge a rare Arsenal chance on 30 minutes when the Israeli released Van Persie, only for the Dutchman's snap-shot to be tipped around the post.2011 September 13, Sam Lyon, “Borussia Dortmund 1 - 1 Arsenal”, in BBC:
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Computing, Engineering, Mathematics, Natural sciences, Physical sciences, Sciences Having a small footprint or performance impact.
Etymology From light (“not heavy”, adjective) + weight (noun).
1
To reduce the amount or weight of.
By extending the producer’s responsibility to the product’s disposal (its post-consumer life), issues previously outside the business calculus become of paramount importance. Because a producer knows it will have to bear the cost of collecting and valorizing the product, it must manage a new set of business matters. Can the packaging be lightweighted? Are the materials all recyclable?1997 December 22, James Salzman, “Sustainable consumption and the law”, in Environmental Law:
The solar photovoltaic array, GPS antennae and telephony antenna all would be lightweighted and integrated into the balloon structure, and the sensor-module would be ruggedized and miniaturized.2002, Edward Teller, Cecil Leith, Gregory Canavan, Lowell Wood, “Long-Range Weather Prediction III: Miniaturized Distributed Sensors for Global Atmospheric Measurements”, in A. Zichichi, R. Ragaini, editors, International Seminar on Nuclear War and Planetary Emergencies, 26th Session (The Science and Culture Series: Nuclear Strategy and Peace Technology), World Scientific, page 328:
1 more example
According to Klausner, “lightweighting” all cars and planes in the US would save 121 billion litres of fuel a year and cut carbon emissions by about 5 per cent.2015 February 28, Hal Hodson, “Heavy metal is so last year”, in New Scientist, page 23: