1.Definition: painstakingly careful and accurate

"Our accountant is thorough", "Thorough research"

2.Definition: performed comprehensively and completely; not superficial or partial

"Made a thorough search", "Thoroughgoing research"

Related Adjective(s):exhaustive, thoroughgoing

3.Definition: without qualification; used informally as (often pejorative) intensifiers

"A thorough nuisance", "A thoroughgoing villain"

Related Adjective(s):arrant, complete, consummate, everlasting, gross, perfect, pure, sodding, staring, stark, thoroughgoing, unadulterated, utter