Nationalists collecting money for intelligence cell? (6)
I believe the answer is:
neuron
'intelligence cell?' is the definition.
(nerve cell)
'nationalists collecting money' is the wordplay.
'nationalists' becomes 'NN' (an abbreviation for nationalist twice).
'collecting' means one lot of letters goes inside another.
'money' becomes 'euro' (currency of the Eurozone).
'nn' placed around 'euro' is 'NEURON'.
'for' is the link.
(Other definitions for neuron that I've seen before include "Nerve impulse cell" , "Transmitting nerve cell" , "It transmits nerve impulses" , "Transmitter of nerve impulses" , "that makes for nervous transmission" .)