Smooth, extremely atypical variety of footwear (6)
I believe the answer is:
sandal
'variety of footwear' is the definition.
'sandal' can be an answer for 'footwear' (sandal is a kind of footwear). I am not certain of the 'variety of' bit.
'smooth extremely atypical' is the wordplay.
'smooth' becomes 'sand' (sanding is a kind of smoothing).
'extremely' suggests removing the centre (only the extremes of the word are used).
'atypical' with its middle removed is 'al'.
'sand'+'al'='SANDAL'
Can you help me to learn more?
(Other definitions for sandal that I've seen before include "An open shoe for summer" , "Light strapped shoe" , "Light footwear" , "Item of footwear" , "Openwork shoe" .)