Be unable to stand, half -dead before trial (6)
I believe the answer is:
detest
'be unable to stand' is the definition.
(I've seen this before)
'half dead before trial' is the wordplay.
'half' indicates taking half.
'before' says to put letters next to each other.
'trial' becomes 'test' ('test' can be a synonym of 'trial').
'dead' halved is 'de'.
'de'+'test'='DETEST'
(Other definitions for detest that I've seen before include "Dislike thoroughly" , "Deplore" , "Find repulsive" , "Be unable to stand" , "Dislike heartily" .)