Take the stand at trial (6)

I believe the answer is:

attest

'take the stand' is the definition.
('attest' can be a synonym of 'take the stand')

'at trial' is the wordplay.
'trial' becomes 'test' ('test' can be a synonym of 'trial').
'at'+'test'='ATTEST'

(Other definitions for attest that I've seen before include "Offer evidence" , "Adjure" , "Demonstrate" , "Corroborate" , "Give testimony in a court of law" .)

I've seen this clue in The Telegraph.

Want a hint initially instead of a full solution? Install my app