Found sole in dock (7)
I believe the answer is:
pioneer
'found' is the definition.
(thesaurus)
'sole in dock' is the wordplay.
'sole' becomes 'one' ('one' can be a synonym of 'sole').
'in' indicates putting letters inside.
'dock' becomes 'pier' (I've seen this before).
'one' inserted into 'pier' is 'PIONEER'.
(Other definitions for pioneer that I've seen before include "Research leader" , "An explorer in new territory" , "One entering new territory" , "Colonist" , "spacecraft" .)