Welsh associate seen around English coastal feature (5)
I believe the answer is:
beach
'coastal feature' is the definition.
(area on the coast)
'welsh associate seen around english' is the wordplay.
'welsh associate' becomes 'bach' (term of endearment in Welsh).
'seen around' is an insertion indicator.
'english' becomes 'e' (abbreviation).
'bach' placed around 'e' is 'BEACH'.
(Other definitions for beach that I've seen before include "The shore between high and low water-mark" , "Area of land sloping down to water" , "Shore between high and low water marks" , "Pebbly or sandy shore" , "Stretch of coastline" .)