Has to go round RAS to trouble and annoy (6)
I believe the answer is:
harass
'annoy' is the definition.
(I know that annoy is a is a more specific form of the action of harass)
'has to go round ras to trouble' is the wordplay.
'to go round' says to put letters next to each other.
'to trouble' is an anagram indicator.
'has' put after 'ras' is 'rashas'.
'rashas' is an anagram of 'HARASS'.
'and' is the link.
(Other definitions for harass that I've seen before include "Make repeated attacks on" , "Trouble or annoy continuously" , "Nag" , "bug" , "Pester constantly" .)