What certain thieves do in Ulster? (6)
I believe the answer is:
rustle
'what certain thieves do' is the definition.
The definition suggests a singular noun which matches the answer.
'ulster?' is the wordplay.
'ulster' can be anagrammed to 'RUSTLE'.
But, I'm not clear how this is indicated.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for rustle that I've seen before include "Steal cattle in the old West" , "Steal stock" , "Wind-in-leaves noise" , "Result (anag.)" , "Low sound of rubbing" .)