Assiduous
International Standard Bible Encyclopedia · James Orr and contributors
a-sid'-u-us: Occurs only in The Wisdom of Solomon 8:18 the Revised Version (British and American), "In assiduous communing with her is understanding," i.e. "in continued exercise of fellowship." The idea expressed in the adjective is contained in the prepositional prefix, sun of the original suggumnasia, giving the verb intensive force.
Source of the article
International Standard Bible Encyclopedia — James Orr, general editor and contributors; CrossWire SWORD module ISBE 2.2
Bible Strong digital edition from CrossWire module 2.2; historical scholarship originally published in 1915