abstrus

Etymology
, perfect passive participle of.

Adjective

 * 1)  abstruse

Etymology
.

Adjective

 * 1) abstruse

Usage notes
A large portion of German speakers confounds this with or believes both to have the same meaning. The meaning "difficult to understand, unclear" is almost never applied in everyday speech.

Adverb

 * 1) abstrusely

Etymology
.

Adjective

 * 1) abstruse

Etymology
From.

Adjective

 * 1) abstruse, difficult to understand
 * 2) nebulous, obscure, mysterious