Webster's Writer's Dictionary

AMAIN

A*main" [Pref. a- + main. See 2d Main, n.]

1. With might; with full force; vigorously; violently; exceedingly. They on the hill, which were not yet come to blows, perceiving the fewness of their enemies, came down amain. Milton. That striping giant, ill-bred and scoffing, shouts amain. T. Parker.

2. At full speed; in great haste; also, at once. "They fled amain." Holinshed.

AMAIN

A*main" [F. amener. See Amenable.] (Naut.)

To lower, as a sail, a yard, etc.

AMAIN

A*main" (Naut.)

To lower the topsail, in token of surrender; to yield.