Adjective: from. Latin inquīsītus, pa. pple. of inquīrĕre to inquire
Verb: from Latin inquīsīt-, ppl. stem of inquīrĕre to inquire
perhaps back-formation from inquisition
1639 - Paolo Servita's (P. Sarpi) History of the Inquisition, Robert Gentilis;
see below from E-NED
From: The Life of the Honourable Sir Dudley North, Knt.
By Roger North, 1744