The Collaborative International Dictionary of English v.0.48:

Rarely \Rare"ly\ (r[^a]r"l[y^]), adv.
   1. In a rare manner or degree; seldom; not often; as, things
      rarely seen.
      [1913 Webster]

   2. Finely; excellently; with rare skill. See 3d Rare, 2.
      [1913 Webster]

            The person who played so rarely on the flageolet.
                                                  --Sir W.
                                                  Scott.
      [1913 Webster]

            The rest of the apartments are rarely gilded.
                                                  --Evelyn.
      [1913 Webster]

WordNet (r) 3.0 (2006):

rarely
    adv 1: not often; "we rarely met" [syn: rarely, seldom]
           [ant: frequently, oft, often, oftentimes,
           ofttimes]