Brook heard in Welsh resort (4)
I believe the answer is:
rhyl
'welsh resort' is the definition.
(I've seen this before)
'brook heard' is the wordplay.
'brook' becomes 'rill' (I've seen this in another clue).
'heard' indicates a 'sounds like' (homophone) clue.
'rill' sounds like 'RHYL'.
'in' acts as a link.
(Other definitions for rhyl that I've seen before include "Welsh resort near Colwyn Bay" , "Welsh location" , "North Welsh resort" , "Seaside resort in Denbighshire" , "Clwyd resort" .)