Passionate strange event over The Border (8)
I believe the answer is:
vehement
'passionate' is the definition.
(I've seen this before)
'strange event over the border' is the wordplay.
'strange' indicates anagramming the letters.
'over' means one lot of letters goes inside another.
'the border' becomes 'hem' (I've seen this in another clue).
'event' is an anagram of 'veent'.
'veent' enclosing 'hem' is 'VEHEMENT'.
(Other definitions for vehement that I've seen before include "Vigorously emphatic" , "Even them being intense, showing strong feeling" , "Showing strong feeling, impassioned" , "Emphatic, intense" , "Vet he-men showing strong feeling" .)