(noun, adjective, preposition)


1. painstakingly careful and accurate

- our accountant is thorough

- thorough research

Similar word(s): careful

2. performed comprehensively and completely; not superficial or partial

- made a thorough search

- thoroughgoing research

Similar word(s): complete, exhaustive, thoroughgoing

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

- a thorough nuisance

- a thoroughgoing villain

Similar word(s): unmitigated, arrant, complete, everlasting, gross, perfect, pure, sodding, staring, stark, thoroughgoing, unadulterated, utter

Sentences with thorough as an adjective:

- The Prime Minister announced a thorough investigation into the death of a father of two in police custody.

- He is the most thorough worker I have ever seen.

- The infested house needs a thorough cleansing before it will be inhabitable.

- It is a thorough pleasure to see him beg for mercy.


1. (Britain, dialect) A furrow between two ridges, to drain off the surface water.


1. (obsolete) Through. [9th-19th c.]