Heading north, salesperson encountered anger (6)
I believe the answer is:
temper
'anger' is the definition.
(temper is a kind of anger)
'heading north salesperson encountered' is the wordplay.
'heading north' says the letters should be written backwards.
'salesperson' becomes 'rep' (I've seen this before).
'encountered' becomes 'met' ('meet' can be a synonym of 'encounter').
'rep'+'met'='repmet'
'repmet' back-to-front is 'TEMPER'.
(Other definitions for temper that I've seen before include "Harden metal by heating and cooling" , "Moderate - anger" , "Frame of mind" , "Display of anger" , "Volatile anger - don't lose it" .)