Old English ful occasionally meant "ugly" (as contrasted with fæger (adj.), modern fair (adj.)), and this sense became frequent in Middle English. The cognate in Swedish is the usual word for "ugly." Of weather from mid-14c. In the sporting sense of "irregular, unfair, contrary to established rule or practice" it is first attested 1797, though foul play is recorded from mid-15c. Baseball sense of "out of play" attested by 1860.
Old English weder "air, sky; breeze, storm, tempest," from Proto-Germanic *wedra- "wind, weather" (source also of Old Saxon wedar, Old Norse veðr, Old Frisian, Middle Dutch, Dutch weder, Old High German wetar, German Wetter "storm, wind, weather"), traditionally said to be from PIE *we-dhro-, "weather" (source also of Lithuanian vėtra "storm," Old Church Slavonic vedro "good weather"), suffixed form of root *we- "to blow." But Boutkan finds this "problematic from a formal point of view" and finds only the Slavic word a likely cognate.
Alteration of -d- to -th- begins late 15c., though such pronunciation may be older (see father (n.)). In nautical use, as an adjective, "toward the wind" (opposed to lee).
Greek had words for "good weather" (aithria, eudia) and words for "storm" and "winter," but no generic word for "weather" until kairos (literally "time") began to be used as such in Byzantine times. Latin tempestas "weather" (see tempest) also originally meant "time;" and words for "time" also came to mean weather in Irish (aimsir), Serbo-Croatian (vrijeme), Polish (czas), etc. Weather-report is from 1863. Weather-breeder "fine, serene day which precedes and seems to prepare a storm" is from 1650s.
Surnames Fairweather, Merriweather probably reflect disposition; medieval lists and rolls also include Foulweder, Wetweder, Strangweder.
c. 1200, "fighting equipment, armor and weapons," probably from Old Norse gørvi (plural gørvar) "apparel, gear," related to görr, gørr, gerr "skilled, accomplished; ready, willing," and to gøra, gørva "to make, construct, build; set in order, prepare," a very frequent verb in Old Norse, used in a wide range of situations from writing a book to dressing meat.
This is from Proto-Germanic *garwjan "to make, prepare, equip" (source also of Old English gearwe "clothing, equipment, ornament," which may be the source of some uses; Old Saxon garwei; Dutch gaar "done, dressed;" Old High German garo "ready, prepared, complete," garawi "clothing, dress," garawen "to make ready;" German gerben "to tan"). Old English glossed Latin apparatus with gearcung.
From early 14c. as "wearing apparel, clothes, dress;" also "harness of a draught animal; equipment of a riding horse." From late 14c. as "equipment generally; tools, utensils," especially the necessary equipment for a certain activity, as the rigging of a sailing ship. It was used generically as an affix in 16c. canting slang for "thing, stuff, material."
Meaning "toothed wheel in machinery" is attested by 1520s; specific mechanical sense of "parts by which a motor communicates motion" is from 1814; specifically of a vehicle (bicycle, automobile, etc.) by 1888. Slang for "male sex organs" from 1670s.
