from the GNU version of the Collaborative International Dictionary of English
- adv. In an abstruse manner.
from The Century Dictionary and Cyclopedia
- In an abstruse or recondite manner; in a manner not to be easily understood.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adv. in a manner difficult to understand
abstruse + -ly (Wiktionary)