Napoleon’s vital fluid piped (4)
I believe the answer is:
sang
'piped' is the definition.
The answer and definition can be both to do with communicating as well as being past participle verbs.
Maybe you can see an association between them that I don't see?
'napoleon's vital fluid' is the wordplay.
I cannot really see how this works, but
'fluid' could be 'n' (N is an example) and 'n' is found within the answer.
The remaining letters 'sag' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sang that I've seen before include "Did numbers" , "Chinese organ" , "Spilt the beans" , "Took part in a vocal performance" , "Was in a choir" .)