The Collaborative International Dictionary of English v.0.48:

Humbly \Hum"bly\, adv.
   With humility; lowly. --Pope.
   [1913 Webster]

WordNet (r) 3.0 (2006):

humbly
    adv 1: in a humble manner; "he humbly lowered his head" [syn:
           humbly, meekly]
    2: in a miserly manner; "they lived meanly and without
       ostentation" [syn: meanly, humbly]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "humbly":
   abjectly, apologetically, contritely, meekly, modestly,
   on all fours, on bended knee, penitentially, penitently, quietly,
   repentantly, sheepishly, submissively, unassumingly, unobtrusively,
   unostentatiously, unpresumptuously, unpretendingly,
   unpretentiously, with bated breath, with due deference,
   without ceremony