Source : Webster's Revised Unabridged Dictionary (1913)

Free-soil \Free"-soil`\, a.
   Pertaining to, or advocating, the non-extension of slavery;
   -- esp. applied to a party which was active during the period
   1846-1856. [U.S.] -- {Free"soil`er}, n. [U.S.] --
   {Free"-soil`ism}, n. [U.S.]

Source : WordNet®

free-soil
     adj : where slavery was prohibited; "a free-soil state" [syn: {slaveless}]