Developed the pier end, possibly (7)
I believe the answer is:
ripened
'developed' is the definition.
(thesaurus)
'pier end possibly' is the wordplay.
'possibly' indicates an anagram.
'pier'+'end'='pierend'
'pierend' anagrammed gives 'RIPENED'.
'the' acts as a link.
(Other definitions for ripened that I've seen before include "(Of fruit) matured" , "Matured, aged" , "Became mature" .)