Source : Webster's Revised Unabridged Dictionary (1913)

Peradventure \Per`ad*ven"ture\, adv. & conj. [OE. per aventure,
   F. par aventure. See {Per}, and {Adventure}.]
   By chance; perhaps; it may be; if; supposing. ``If
   peradventure he speak against me.'' --Shak.

         Peradventure there be fifty righteous within the city.
                                                  --Gen. xviii.
                                                  24.

Peradventure \Per`ad*ven"ture\, n.
   Chance; hap; hence, doubt; question; as, proved beyond
   peradventure. --South.

Source : WordNet®

peradventure
     adv : by chance; "perhaps she will call tomorrow"; "we may
           possibly run into them at the concert"; "it may
           peradventure be thought that there never was such a
           time" [syn: {possibly}, {perchance}, {perhaps}, {maybe},
            {mayhap}]