Spy chief regularly highlighted our so-called clout (6)
I believe the answer is:
muscle
'clout' is the definition.
(I've seen this in another clue)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for muscle that I've seen before include "Force; a body tissue" , "Body tissue - strength" , "Fibrous tissue with the ability to contract" , "Eg, biceps" , "Brawn" .)