retruse

Etymology
From, past participle of.

Adjective

 * 1) Thrust backward; retruding.
 * 2)  abstruse
 * 3) * 1662,, Preface to A Collection of Several Philosophical Writings
 * I have a sense of something in me while I thus speak, which I must confess is of so retruse a nature that I want a name for it, unless I should adventure to term it