Wordnet 3.0
ADJECTIVE (1)
1. 
 diligent and thorough in inquiry or investigation; 
- Example: "a probing inquiry"- Example: "a searching investigation of their past dealings"[syn: inquisitory, probing, searching]
WordNet (r) 3.0 (2006):
inquisitory
    adj 1: diligent and thorough in inquiry or investigation; "a
           probing inquiry"; "a searching investigation of their
           past dealings" [syn: inquisitory, probing,
           searching]