Realistic after rehearsal, shortened a line (9)
I believe the answer is:
practical
'realistic' is the definition.
('practical' is associated in meaning with 'realistic')
'rehearsal shortened a line' is the wordplay.
'rehearsal' becomes 'practice' (I've seen this before).
'shortened' means to remove the last letter.
'line' becomes 'l'.
'practice' with its final letter taken away is 'practic'.
'practic'+'a'+'l'='PRACTICAL'
'after' is the link.
(Other definitions for practical that I've seen before include "Feasible; realistic" , "Experiment" , "description of Macavity and Bustopher Jones?" , "Given to action rather than theory" , "Down to earth - like Eliot's Cats" .)