Source : Webster's Revised Unabridged Dictionary (1913)

Closely \Close"ly\, adv.
   1. In a close manner.

   2. Secretly; privately. [Obs.]

            That nought she did but wayle, and often steepe Her
            dainty couch with tears which closely she did weepe.
                                                  --Spenser.

Source : WordNet®

closely
     adv 1: in a close relation or position in time or space; "the
            onsets were closely timed"; "houses set closely
            together"; "was closely involved in monitoring daily
            progress"
     2: in a close manner; "the two phenomena are intimately
        connected"; "the person most nearly concerned" [syn: {intimately},
         {nearly}]
     3: in an attentive manner; "he remained close on his guard"
        [syn: {close}, {tight}]