Chief thanks Centrelink for service (8)
I believe the answer is:
maintain
'service' is the definition.
The answer and definition can be both related to thinking as well as being verbs in their base form.
Perhaps you can see an association between them that I don't see?
'chief thanks centrelink' is the wordplay.
'chief' becomes 'main' (synonyms).
'thanks' becomes 'ta' (UK informal version of 'thank you').
'centrelink' becomes 'in' (I can't explain this - if you can you should give a lot more credence to this answer).
'main'+'ta'+'in'='MAINTAIN'
'for' is the link.
Can you help me to learn more?
(Other definitions for maintain that I've seen before include "finance" , "Keep in existence or in repair" , "Keep - support" , "Profess" , "Keep in a good state of repair" .)