Feeling upon missing one's verdict (8)
I believe the answer is:
sentence
'verdict' is the definition.
(thesaurus)
'feeling upon missing one's' is the wordplay.
'feeling' becomes 'sentience' (I've seen this before).
'upon missing' suggests deleting specific letters.
'one' becomes 'i' (Roman numeral).
'sentience' with 'i' taken away is 'SENTENCE'.
(Other definitions for sentence that I've seen before include "Term of imprisonment" , "Punishment awarded by court, or a set of words" , "expressed in a few words" , "Group of words with verb" , "Judgment on convict" .)