Run a bit (4)
I believe the answer is:
dash
I believe this is a double definition.
'run' is the first definition.
(dash is a kind of run)
'a bit' is the second definition.
(thesaurus)
(Other definitions for dash that I've seen before include "sudden advance" , "Vivacity" , "Morse code symbol" , "Striking" , "hasty journey" .)