English

Adverb

abstrusely ‎(comparative more abstrusely, superlative most abstrusely)

1. In an abstruse manner. [First attested in the early 17^th century.]^[1]

References

1. ↑ Lesley Brown (editor), The Shorter Oxford English Dictionary, 5th edition (Oxford University Press, 2003 [1933], ISBN 978-0-19-860575-7), page 10