Leading party thrashing youths around college to intimidate (5,3)
I believe the answer is:
psych out
'intimidate' is the definition.
(I've seen this before)
'leading party thrashing youths around college to' is the wordplay.
'leading party thrashing youths' becomes 'psych' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'around' indicates an anagram.
'college' becomes 'u' (abbreviation for University).
'u'+'to'='uto'
'uto' with letters rearranged gives 'out'.
'psych'+'out'='PSYCH OUT'
Can you help me to learn more?
(Other definitions for psych out that I've seen before include "Undermine" , "intimidate" , "cow" , "Play mental games" , "Guess correctly the intentions of another (informal)" .)