Practice on funeral carriage (8)
I believe the answer is:
rehearse
'practice' is the definition.
(synonyms)
'on funeral carriage' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'funeral carriage' becomes 'hearse' (I've seen this before).
're'+'hearse'='REHEARSE'
(Other definitions for rehearse that I've seen before include "Practise before a public performance" , "Practise play in theatre" , "What actor does to prepare for play" , "Prepare for a stage production" , "Go over" .)