Make someone take notice? (6)
I believe the answer is:
resign
'make' is the definition.
The definition and answer can be both related to thinking as well as being verbs in their base form.
Perhaps there's a link between them I don't understand?
'someone take notice?' is the wordplay.
'someone take' becomes 're' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'notice?' becomes 'sign' (notice is a kind of sign).
're'+'sign'='RESIGN'
Can you help me to learn more?
(Other definitions for resign that I've seen before include "admit defeat" , "Give up position" , "Quit" , "Abdicate" , "Give up one's post" .)