Traveller highwayman initially steals from and beats (6)
I believe the answer is:
throbs
'beats' is the definition.
(I know this)
'traveller highwayman initially steals from' is the wordplay.
'initially' indicates taking the first letters.
'steals from' becomes 'robs' (I've seen this in another clue).
The first letters of 'traveller highwayman' is 'th'.
'th'+'robs'='THROBS'
'and' acts as a link.
(Other definitions for throbs that I've seen before include "Pounds" , "Beats as a pulse" , "Beats like the heart" , "Pulsates, with pain perhaps" , "Beats with persistent rhythm, as heart does" .)