Row close to huge wave (5)
I believe the answer is:
spate
'wave' is the definition.
'row close to huge' is the wordplay.
'row' becomes 'spat' (a spat is a disagreement or argument).
'close to' says to take the final letters (the close/ending of).
The final letter of 'huge' is 'e'.
'spat'+'e'='SPATE'
(Other definitions for spate that I've seen before include "Sudden river flood" , "Fast outpouring" , "Suddenly got a lot" , "Tapes found in sudden flood" , "Deluge" .)