Leave for the seaside (6)
I believe the answer is:
strand
I believe this is a double definition.
'leave' is the first definition.
(I know that strand is a more specific form of the action abandon)
'seaside' is the second definition.
(thesaurus)
'for the' acts as a link.
(Other definitions for strand that I've seen before include "Beach or single hair" , "Shore; single thread" , "Abandon on the seashore" , "Lock of hair" , "Stretch of sand" .)