"Shaker" 1781, antedates OED sense 4.b. 1784-

[Joel S. Berson]

Thomas's Massachusetts Spy, Or, American Oracle of Liberty.
1781 May 4, page 3, col. 2.  [EAN]

 From several parts of the country, we are informed of the
extraordinary behavior of a number of people, who appear to be
actuated by a king of religious frenzy; they are commonly called Shakers.

[The remainder of the article, an account of the adultery of two
Shakers, is almost certainly false.  There was a case of adultery
tried at the same court (Northampton) about 10 days before this
newspaper issue, but there is no connection with the Shakers in any
other independent source.]

antedates OED2 "shaker"  sense 4.b.  1784-.

There are a number of other hits in EAN for "Shaker" in 1781 and the
next few years.

Joel

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