Started to avoid good head (4)
I believe the answer is:
bean
'head' is the definition.
(bean is a kind of head)
'started to avoid good' is the wordplay.
'started' becomes 'began' ('begin' can be a synonym of 'start').
'to avoid' is a deletion indicator.
'good' becomes 'g' (abbreviation).
'began' with 'g' taken out is 'BEAN'.
(Other definitions for bean that I've seen before include "Edible seed" , "comic character" , "Seed; head" , "Haricot, for example" , "coffee, perhaps" .)