1. boxers or wrestlers competing in a weight class typically between featherweight and welterweight
Usage: sports
2. people who cannot drink much alcohol before becoming intoxicated
Usage: informal
3. people who lack influence, importance, or ability in a particular area
Usage: informal; often derogatory

Examples

• The gym trains several promising lightweights for upcoming tournaments.
• Both fighters are lightweights, so it should be an evenly matched bout.
• We’re all lightweights when it comes to drinking, so we’ll stick to one beer each.
• Don’t invite those lightweights to the wine tasting – they’ll be tipsy after one glass.
• The committee is full of political lightweights with no real experience.
• These academic lightweights shouldn’t be making decisions about curriculum.
• The company’s management team consists mainly of lightweights who lack vision.