The Collaborative International Dictionary of English v.0.48:

Rife \Rife\, a. [AS. r[imac]f abundant, or Icel. r[imac]fr
   munificent; akin to OD. riff, rijve, abundant.]
   1. Prevailing; prevalent; abounding.
      [1913 Webster]

            Before the plague of London, inflammations of the
            lungs were rife and mortal.           --Arbuthnot.
      [1913 Webster]

            Even now the tumult of loud mirth
            Was rife, and perfect in may listening ear.
                                                  --Milton.
      [1913 Webster]

   2. Having power; active; nimble. [Obs.]
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            What! I am rife a little yet.         --J. Webster.
      [1913 Webster] -- Rife"ly, adv. -- Rife"ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

rife
    adj 1: most frequent or common; "prevailing winds" [syn:
           prevailing, prevalent, predominant, dominant,
           rife]
    2: excessively abundant [syn: overabundant, plethoric,
       rife]