The Collaborative International Dictionary of English v.0.48:

Intently \In*tent"ly\, adv.
   In an intent manner; as, the eyes intently fixed.

   Syn: Fixedly; steadfastly; earnestly; attentively;
        sedulously; diligently; eagerly.
        [1913 Webster]

WordNet (r) 3.0 (2006):

intently
    adv 1: with strained or eager attention; "listened intently";
           "stood watching intently"

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "intently":
   absorbedly, advertently, ardently, assiduously, attentively,
   closely, continuously, determinedly, devotedly, devoutly, doggedly,
   eagerly, earnestly, engrossedly, fervently, fervidly, fixedly,
   heartily, heatedly, heedfully, impassionedly, intensely,
   interestedly, keenly, mindfully, observantly, passionately,
   perfervidly, preoccupiedly, raptly, regardfully, seriously,
   sharply, sincerely, steadfastly, steadily, studiously,
   unflinchingly, unremittingly, vehemently, with attention,
   with interest, with rapt attention, with undivided attention,
   without distraction, zealously