Short note rather crass line ends (5)
I believe the answer is:
terse
'short' is the definition.
(synonyms)
'note rather crass line ends' is the wordplay.
'note' becomes 'te' (musical note).
'ends' suggests the final letters.
The final letters of 'rather crass line' are 'rse'.
'te'+'rse'='TERSE'
(Other definitions for terse that I've seen before include "Crisp and brief" , "Of speech, short and pithy" , "Briefly expressed" , "Curt among trees" , "Short, abrupt" .)