I. ˈfa-(ˌ)lō adjective
Etymology: Middle English falow, from Old English fealu; akin to Old High German falo pale, fallow, Latin pallēre to be pale, Greek polios gray
Date: before 12th century
: of a light yellowish-brown color
II. noun
Etymology: Middle English falwe, falow, from Old English fealg — more at felly
Date: before 12th century
1. : usually cultivated land that is allowed to lie idle during the growing season
2. obsolete : plowed land
3. : the state or period of being fallow
4. : the tilling of land without sowing it for a season
III. transitive verb
Date: 15th century
: to plow, harrow, and break up (land) without seeding to destroy weeds and conserve soil moisture
IV. adjective
Date: 15th century
1. : left untilled or unsown after plowing
2. : dormant , inactive — used especially in the phrase to lie fallow
at this very moment there are probably important inventions lying fallow — Harper's
• fal·low·ness noun