In a court case, an expert witness is someone such as a doctor or other professional who testifies about and gives opinions on subjects and issues that have been raised in the particular court case.
Flynn often testifies as an expert witness in court cases.
expert witness in British English
(ˈɛkspɜːt ˈwɪtnəs)
noun
law
an expert in a particular field who offers his or her specialized knowledge in a court of law
I have been accepted as an expert witness on dog behaviour by law courts.
Examples of 'expert witness' in a sentence
expert witness
He is secretary for a farming organisation, acts as an expert witness in equine law cases and owns a couple of shops.
The Sun (2008)
Nearly one in three expert witnesses say they are under pressure to change their reports to favour the client, a new survey shows.