Possible threat from men by European university (2,4)
I believe the answer is:
or else
'possible threat' is the definition.
'or else' can be an answer for 'threat' (I have seen 'a threat' mean 'or else' so perhaps 'threat' could also mean 'or else'). I'm unsure of the 'possible' bit.
'men by european university' is the wordplay.
'men' becomes 'or' (military abbreviation for Other Ranks).
'by' is a charade indicator (letters next to each other).
'european' becomes 'E' (abbreviation e.g. EU).
'university' becomes 'lse' (London School of Economics).
'or'+'e'+'lse'='OR ELSE'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for or else that I've seen before include "If not, then - sounds like a threat" , "Statement that threatens" , "Threatening phrase" , "Otherwise - may be threatening" , "Do it . . . . . . - an informal warning" .)