Seaside attraction noble mentioned in speech (4)
I believe the answer is:
pier
'seaside attraction' is the definition.
(structure by the sea)
'noble mentioned in speech' is the wordplay.
'noble' becomes 'peer' (peers are members of the nobility).
'mentioned in speech' indicates a 'sounds like' (homophone) clue.
'peer' sounds like 'PIER'.
(Other definitions for pier that I've seen before include "Buttress; landing place" , "Platform out to sea" , "Breakwater; arch pillar" , "Landing-stage or promenade" , "seaside location" .)