Assuming high opinion of own self, exerted leverage in speech (5)
I believe the answer is:
pride
'assuming high opinion of own self exerted leverage in speech' is the definition.
I can't judge whether this defines the answer.
'assuming high opinion of own self' is the wordplay.
'assuming high opinion of' becomes 'pre' (I am not sure about this - if you are sure you should believe this answer much more).
'own' means one lot of letters goes inside another.
'self' becomes 'id'.
'pre' going around 'id' is 'PRIDE'.
Can you help me to learn more?
(Other definitions for pride that I've seen before include "''. . . . . goeth before a fall''" , "Leonine family" , "big cats" , "Hubris" , "They say it comes before a fall" .)