Oh, back Ted; bringing in the Chief, that’s impulsive! (3-6)
I believe the answer is:
hot-headed
'impulsive' is the definition.
(I've seen this before)
'oh back ted bringing in the chief' is the wordplay.
'back' says the letters should be written backwards.
'bringing in' means one lot of letters goes inside another.
'the chief' becomes 'head' (synonyms).
'oh' back-to-front is 'ho'.
'ted' going around 'head' is 'theaded'.
'ho'+'theaded'='HOT-HEADED'
'that's' is the link.
(Other definitions for hot-headed that I've seen before include "Impulsive" , "Impetuous, quick-tempered" , "Impetuous, rash" .)