English Liberal with smooth side (6)
I believe the answer is:
eleven
'side' is the definition.
(I've seen this before)
'english liberal with smooth' is the wordplay.
'english' becomes 'e' (abbreviation).
'liberal' becomes 'l' (abbreviation).
'with' says to put letters next to each other.
'smooth' becomes 'even' ('even' can be similar in meaning to 'smooth').
'e'+'l'+'even'='ELEVEN'
(Other definitions for eleven that I've seen before include "'Legs' bingo number" , "XI as Roman numeral" , "Football side" , "Number, on a team perhaps" , "Enough for a soccer side" .)