Bubbly sort has no front; jerk's ultimately lacking (4)
I believe the answer is:
asti
'bubbly sort' is the definition.
The definition suggests a singular noun which matches the answer.
'no front jerk's ultimately lacking' is the wordplay.
'no front' becomes 'as' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'jerk' becomes 'tic' (jerking movement by the body).
'ultimately lacking' means to remove the last letter.
'tic' with its last letter taken off is 'ti'.
'as'+'ti'='ASTI'
'has' acts as a link.
Can you help me to learn more?
(Other definitions for asti that I've seen before include "- spumante, It. wine" , "town in Italy" , "Italian wine - (then change a letter for ...)" , "It's a (anag) - wine" , "Sparkling wine named after an Italian Piedmont town" .)