[f. BOOM v.3 2.] One who ‘booms’ or pushes an enterprise. U.S. slang.

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1883.  Times, 26 Sept., 8/2. ‘Uncle Rufus’ … is a North-Western ‘boomer’ of great earnestness.

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1885.  Boston (Mass.) Jrnl., 19 Aug., 2/4. The Oklahoma boomers.

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