Cleverly leading a seaman to a silly conclusion (4)
I believe the answer is:
ably
'cleverly' is the definition.
(thesaurus)
'leading a seaman to a silly conclusion' is the wordplay.
'leading' says to put letters next to each other.
'a seaman' becomes 'ab' (short for able seaman).
'to a silly conclusion' becomes 'ly' (I am not sure about this - if you are sure you should believe this answer much more).
'ab' put next to 'ly' is 'ABLY'.
Can you help me to learn more?
(Other definitions for ably that I've seen before include "With competence" , "In a competent fashion" , "well" , "In proficient manner" , "With great skill" .)