The Collaborative International Dictionary of English v.0.48:
Solitarily \Sol"i*ta*ri*ly\, adv. In a solitary manner; in solitude; alone. --Mic. vii. 14. [1913 Webster]WordNet (r) 3.0 (2006):
solitarily adv 1: in solitude; "a hermit chooses to live solitarily"