Assumed one's permitted to keep parking inside (8)
I believe the answer is:
implicit
'assumed' is the definition.
(similar in meaning)
'one's permitted to keep parking inside' is the wordplay.
'one's' becomes 'I'm' ('one is' is a formal way of saying 'I am').
'permitted' becomes 'licit' (licit means allowed or permitted).
'to keep' indicates putting letters inside.
'parking inside' becomes 'p' (abbreviation on road signs. I am not sure about the 'inside' bit.).
'im'+'licit'='imlicit'
'imlicit' placed around 'p' is 'IMPLICIT'.
Can you help me to learn more?
(Other definitions for implicit that I've seen before include "Unspoken" , "Not in so many words" , "Indirectly implied" , "meaning is obvious?" , "Understood but not openly stated" .)