Witness admits terms of decision bias soundness of judgement (5)
I believe the answer is:
sense
'soundness of judgement' is the definition.
'sense' can be an answer for 'judgement' (sense is a kind of judgement). I am not sure about the 'soundness of' bit.
'witness admits terms of decision bias' is the wordplay.
'witness' becomes 'see' (synonyms).
'admits' means one lot of letters goes inside another (to admit is to allow in).
'terms of' indicates one should take the final letters (term can mean the end of something).
The final letters of 'decision bias' are 'ns'.
'see' placed around 'ns' is 'SENSE'.
Can you help me to learn more?
(Other definitions for sense that I've seen before include "Eg, taste or touch" , "Sound practical judgment" , "Feel intuitively" , "Meaning; perception" , "Purport" .)