Head from German city, going north, not east (4)
I believe the answer is:
ness
'not east' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'head from german city going north' is the wordplay.
'head from' means to remove the first letter (I've seen 'heading from' mean this (remove the letter which heads the word)).
'german city' becomes 'essen' (I've seen this before).
'going north' says the letters should be written backwards.
'essen' with its initial letter taken off is 'ssen'.
'ssen' in reverse letter order is 'NESS'.
(Other definitions for ness that I've seen before include "Scottish Loch famed for monster" , "Famous loch" , "Where you're reputed to see monster" , "Headland, cape" , "Eliot -, led effort against Al Capone; Scots loch" .)