Charles Ellicott Commentary Jeremiah 51:2

"And I will send unto Babylon strangers, that shall winnow her; and they shall empty her land: for in the day of trouble they shall be against her round about." — Jeremiah 51:2 (ASV)

Fanners, that shall fan her. —The Hebrew word as it stands means “strangers,” but a change of the vowel-points would etymologically give “winnowers” or “fanners,” though the word is not found elsewhere. On the whole, it would seem best to accept the meaning of “strangers,” the prophet connecting it with the verb for “fan,” which contains the same consonants, for the sake of a rhythmical assonance. The imagery in either case is that of the familiar picture of the “threshing-floor,” where the “strong wind” scatters the chaff in all directions (Psalms 1:4; Psalms 35:5; Isaiah 17:13; Isaiah 29:5). The word for “empty” is the same as that used with an emphatic significance in Jeremiah 19:7.