With head lowered, shock French friend advancing wave (7)
I believe the answer is:
tsunami
'wave' is the definition.
(tsunami is a kind of wave)
'with head lowered shock french friend advancing' is the wordplay.
I cannot really see how this works, but
'friend' could be 'ami' ('friend' in French) and 'ami' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tsunami that I've seen before include "Large tidal wave" , "big wave" , "Seismic sea wave" , "Huge wave caused by earth tremor" , "Great, fast-moving sea wave" .)