1. (v. t.) To follow up step by step by patient inquiry or observation; to trace or track mentally; to search into; to inquire and examine into with care and accuracy; to find out by careful inquisition; as, to investigate the causes of natural phenomena.

2. (v. i.) To pursue a course of investigation and study; to make investigation.

air analyze canvass comment upon consider controvert deal with debate deliberate deliberate upon delve into dig into discourse about discuss examine exchange views explore fathom go go into handle indagate inquire into knock around look into pass under review peer into plumb poke into probe pry pry into rap reason reason about reason the point research review scrutinize search into sift sound study take up talk talk about talk of talk over thresh out treat ventilate winnow