Pulsate; flog (4)
I believe the answer is:
beat
This clue is a double definition.
'pulsate' is the first definition.
(I've seen this before)
'flog' is the second definition.
(I've seen this before)
(Other definitions for beat that I've seen before include "Master" , "Tan" , "Defeat; pulsate" , "Thrash with rhythm?" , "Rhythmic musical unit" .)