Forceful archdeacon takes time crossing eastern border (8)
I believe the answer is:
vehement
'forceful' is the definition.
(I've seen this before)
'archdeacon takes time crossing eastern border' is the wordplay.
'archdeacon' becomes 'ven' (abbreviation for The Venerable).
'takes time' becomes 't' (I can't explain this - if you can you should give a lot more credence to this answer).
'crossing' means one lot of letters goes inside another (to cross can mean to go over or around).
'eastern' becomes 'e'.
'border' becomes 'hem' (I've seen this in another clue).
'ven'+'t'='vent'
'e'+'hem'='ehem'
'vent' going around 'ehem' is 'VEHEMENT'.
Can you help me to learn more?
(Other definitions for vehement that I've seen before include "Vet he-men showing strong feeling" , "Burning" , "Fervid" , "Showing strong feeling, like even them" , "Zealously forceful" .)