Wordnet 3.0
ADVERB (1)
1.
in an inscrutable manner;
The Collaborative International Dictionary of English v.0.48:
Inscrutably \In*scru"ta*bly\, adv.
In an inscrutable manner.
[1913 Webster]
WordNet (r) 3.0 (2006):
inscrutably
adv 1: in an inscrutable manner