hummer

1. (informal) A Humvee.informal

2. (informal) A hummingbird.Examples: "July roth saw the first spotted egg hardly larger than a “hummer's,” lying in the nest."; "The Sargents' status as hummingbird gurus is unrivaled and well deserved. They began banding hummers back in 1988, when, Bob says, there were only 28 other banders in the country."; "Between high mortality during the first year, natural disaster, pollution, habitat destruction, and the general decline in hummers that has been reported over the last couple of years (responses given to questions fielded by Bird Watchers indicate that there is a real hummer decline), I feel that I did the right thing by taking this bird in."informal

3. (informal) A humdinger; something or someone exceptional or outstanding of their type.Examples: ""Ain't it a hummer of a day?" Jim exclaimed, suddenly, looking toward the valley swimming in a silver mist below us. "By Jiminy! it makes a man feel like living, don't it?""; "Dad's a real hummer at poker."; "Another report: “The queen that I had from you last year has proved a real hummer."informal

4. (slang) A very energetic or lively person; a powerful lively thing.Examples: "I had a thousand liars, perjurers and villains call on me, and six genuine survivors of Lafitte's band; besides quite a delegation of widows and daughters and offspring of the late lamented pirate. No less than ten of his widows turned up; Jean must have been a hummer!"; "He drinks, swears, smokes, plays cards, and when it comes to ragtime, my boy, he can beat any man on the stage. Oh, you bet he is a hummer, all right!"slang

5. (slang, dated) A place, event etc. that is bustling or full of activity.Examples: "[Heading: The Conferences] St. Joe was a hummer. It was largely attended, enthusiastic, and splendidly entertained by the pastor, Rev. J. Simons, and his people."; "“The best Reunion class of all will be back in Jersey on June 6 to 10, for a real off-year reunion, which will be a hummer.[…]”"; "The courtroom was a real hummer of activity."datedslang

6. (baseball) A fastball.Examples: "Branca, concentrating so intently that he didn't hear the braying crowd, threw a hummer down the middle."