Definitions of fallow:

• noun:   cultivated land that is not seeded for one or more growing seasons
• adjective:   left unplowed and unseeded during a growing season

  Example: "Fallow farmland"

• adjective:   undeveloped but potentially useful

  Example: "A fallow gold market"

• name:  A surname (very rare: popularity rank in the U.S.: #73108)