In principle, it's said it could be Freud? (10)
I believe the answer is:
headmaster
'in principle it's said it' is the definition.
I can't tell whether this defines the answer.
'be freud?' is the wordplay.
'be' becomes 'head' (heading is a kind of being).
'freud?' becomes 'master' (I can't explain this - if you can you should give a lot more credence to this answer).
'head'+'master'='HEADMASTER'
'could' is the link.
Can you help me to learn more?
(Other definitions for headmaster that I've seen before include "Principal" , "School manager" , "Top (male) teacher" .)