Little girl's dog carrying lead, oddly comical (7)
I believe the answer is:
jocular
'comical' is the definition.
(thesaurus)
'little girl's dog carrying lead oddly' is the wordplay.
'little girl' becomes 'jo' (short for Josephine).
'dog' becomes 'cur' (both can mean a despicable person).
'carrying' means one lot of letters goes inside another.
'oddly' indicates alternate letters (letters in the odd-numbered positions are used).
The alternating letters of 'lead' are 'la'.
'cur' placed around 'la' is 'cular'.
'jo'+'cular'='JOCULAR'
(Other definitions for jocular that I've seen before include "Given to telling gags (and having fun)" , "funny" , "Humorous, joking" , "Humorous or playful" , "With jokes and good humour" .)