The rep is a less worried chap (8)
I believe the answer is:
salesman
'the rep' is the definition.
(I've seen this before)
'a less worried chap' is the wordplay.
'worried' indicates anagramming the letters.
'chap' becomes 'man' (chap can mean a man).
'a'+'less'='aless'
'aless' is an anagram of 'sales'.
'sales'+'man'='SALESMAN'
'is' acts as a link.
(Other definitions for salesman that I've seen before include "Amen, lass, to the seller" , "He used to be known as a commercial traveller" , "Arthur Miller wrote 'Death of a . . . . . . . .'" , "''Death of a ...'' (drama by Arthur Miller)" , "One selling goods" .)