Doctor still taken aback about student's foolish garb (6)
I believe the answer is:
motley
'student's foolish garb' is the definition.
I can't judge whether this defines the answer.
'doctor still taken aback' is the wordplay.
'doctor' becomes 'mo' (medical officer).
'still taken' becomes 'yelt' (I can't explain this - if you can you should believe this answer much more).
'aback' says the letters should be written backwards.
'yelt' written backwards gives 'tley'.
'mo'+'tley'='MOTLEY'
'about' is the link.
Can you help me to learn more?
(Other definitions for motley that I've seen before include "Jester's clothes - varied collection" , "Once a jester's coloured costume - on with it" , "Widespread outbreak of disease" , "various types" , "Miscellaneous" .)