Wander with son, ugly little fellow (6)
I believe the answer is:
stroll
'wander' is the definition.
(thesaurus)
'with son ugly little fellow' is the wordplay.
'with' says to put letters next to each other.
'son' becomes 's' (genealogical abbreviation for son).
'ugly little fellow' becomes 'troll' (fairytale creature).
's' put next to 'troll' is 'STROLL'.
(Other definitions for stroll that I've seen before include "A casual or lazy walk" , "Walk casually" , "Meander" , "Promenade" , "A quiet, pleasant walk" .)