Maybe trunks of wood pronounced over river (9)
I believe the answer is:
beachwear
'maybe trunks' is the definition.
(swimming trunks are a type of beachwear)
'wood pronounced over river' is the wordplay.
'wood' becomes 'beech' (beech is a kind of wood).
'pronounced' indicates a 'sounds like' (homophone) clue.
'over river' becomes 'wear' (river in the north east of England. I am not sure about the 'over' bit.).
'beech' sounds like 'beach'.
'beach'+'wear'='BEACHWEAR'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for beachwear that I've seen before include "holiday gear" , "Bikini, for instance" , "Trunks, bikinis etc" , "skimpy garments" , "Holiday clothing" .)