Hate seeing trusty top steed sent to the knacker's yard (6)
I believe the answer is:
detest
'hate' is the definition.
(synonyms)
'trusty top steed sent to the knacker's yard' is the wordplay.
'top' indicates taking the first letters.
'sent to the knacker's yard' indicates anagramming the letters (letters knackered or broken).
The initial letter of 'trusty' is 't'.
't'+'steed'='tsteed'
'tsteed' is an anagram of 'DETEST'.
'seeing' is the link.
(Other definitions for detest that I've seen before include "Hate a lot" , "can't stand" , "Loathe, hate intensely" , "Deplore" , "Dislike intensely, loathe" .)