Doctor going back to tell fibs to young lass (6)
I believe the answer is:
girlie
'young lass' is the definition.
'girlie' can be an answer for 'lass' (thesaurus). I'm not certain of the 'young' bit.
'doctor going back to tell fibs' is the wordplay.
'doctor' becomes 'rig' (both can mean to manipulate or tamper with).
'going back' says the letters should be written in reverse.
'to tell fibs' becomes 'lie' (I've seen this in another clue).
'rig' reversed gives 'gir'.
'gir'+'lie'='GIRLIE'
'to' is the link.
Can you help me to learn more?
(Other definitions for girlie that I've seen before include "concerned with scantily-clad females" , "featuring scantily clad young women" , "such a magazine?" .)