An archaic word used in Northern England and Scotland. Not much used since the late 1800s, but still peripherally in the public consciousness because Emily Brontë named her one novel Wuthering Heights. The narrator gives a basic definition of wuthering ("'Wuthering' being a significant provincial adjective, descriptive of the atmospheric tumult to which its station is exposed in stormy weather."), but most of us wouldn't know what wuther meant if confronted with it in an unfamiliar context.

1. verb To blow fiercely (said of the wind). To buffet. To blow noisily.

"All t' day a wild hurricane wuther'd throo t' glen,
An' then rush'd like a fiend up to t' heeath;
An' as Peggy sat knittin' shoo said tuv hersen,
"Aw dear! he'll be starruv'd to t' deeath."
-- Yorkshire Dialect Poems (1673-1915) and Traditional Poems, Compiled by F. W. Moorman, 1916

2. noun Wind, especially gusty, blustery, and roaring wind.

"I felt sure now that I was in the pensionnat--sure by the beating rain on the casement; sure by the 'wuther' of wind amongst trees, denoting a garden outside; sure by the chill, the whiteness, the solitude, amidst which I lay."
-- Villette by Charlotte Bronte, 1853

3. adjective Hard blowing (said of wind), especially blowing loudly.

"Wee, crimson-tippet Willie Wink,
Wae's me, drear, dree, and dra,
A waeful thocht, a fearsome flea,
A wuther wind, and a'."
-- What Katy Did by Susan Coolidge, 1872

Wuther is said to have come from the more well-known 'wither', meaning to loose vitality, force, or freshness.


References:
http://encarta.msn.com/encnet/features/dictionary/DictionaryResults.aspx?refid=561511754
http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=wuther
Webster's Third New International Dictionary, 1981
www.Gutenberg.org