Overwhelm, v. t. [imp. & p. p. Overwhelmed; p. pr. & vb. n. Overwhelming.]
1. To cover over completely, as by a great wave; to overflow and bury beneath; to ingulf; hence, figuratively, to immerse and bear down; to overpower; to crush; to bury; to oppress, etc., overpoweringly. The sea overwhelmed their enemies. Ps. lxxviii. 53. Fearfulness and trembling are come upon me, and horror hath overwhelmed me. Ps. lv. 5. Foul deeds will rise, Though all the earth o'erwhelm them. Shak. Gaza yet stands; but all her sons are fallen, All in a moment overwhelmed and fallen. Milton.
2. To project or impend over threateningly. His louering brows o'erwhelming his fair sight. Shak.
3. To cause to surround, to cover. Papin.
1 other Webster entry under this spelling
Overwhelm
, n. The act of overwhelming. [R.]
Shades of meaning
Fernald has no entry of its own for overwhelm; he lists it under hide, involve.
He lists it without comment; the entries above explain its neighbors.