Loathing bowler, possibly on start of delivery (6)
I believe the answer is:
hatred
'loathing' is the definition.
(I've seen this before)
'bowler possibly on start of delivery' is the wordplay.
'bowler possibly' becomes 'hat' (bowler is a type of hat).
'on' becomes 're' ('on' can be mean 'with reference to').
'start of' indicates taking the first letters.
The initial letter of 'delivery' is 'd'.
'hat'+'re'+'d'='HATRED'
(Other definitions for hatred that I've seen before include "Animus" , "Extreme dislike and enmity" , "'Loathing, enmity (6)'" , "Intense dislike" , "Deep dislike and aversion" .)