Morse code component (4)
I believe the answer is:
dash
'morse code component' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for dash that I've seen before include "Vivacity" , "Stylish vigour; frustrate (hopes)" , "Striking" , "Morse code symbol" , "Run hurriedly; hyphen" .)