Son swamped by stream of water? It’s fun (4)
I believe the answer is:
jest
'it's fun' is the definition.
(I've seen this before)
'son swamped by stream' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'swamped by' indicates putting letters inside.
'stream' becomes 'jet'.
's' placed inside 'jet' is 'JEST'.
'of water?' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for jest that I've seen before include "Witty remark" , "In ____, playfully" , "attempt at humour" , "Ridicule" , "Joke, fool about" .)