Wave finally at son with a friend in Paris (7)
I believe the answer is:
tsunami
'wave' is the definition.
(tsunami is a kind of wave)
'finally at son with a friend in paris' is the wordplay.
'finally' suggests the final letters.
'son with' becomes 'sun' (I can't justify this - if you can you should believe this answer much more).
'a friend in paris' becomes 'ami' (French for 'friend').
The final letter of 'at' is 't'.
't'+'sun'+'ami'='TSUNAMI'
Can you help me to learn more?
(Other definitions for tsunami that I've seen before include "Large tidal wave" , "stormy sea" , "Great, fast-moving sea wave" , "Huge tidal wave that causes great damage and loss of life" , "I am nuts! (anag)" .)