Novel with expression of amusement one cheers (6)
I believe the answer is:
lolita
'novel' is the definition.
(I've seen this before)
'with expression of amusement one cheers' is the wordplay.
'with' is a charade indicator (letters next to each other).
'expression of amusement' becomes 'lol' (abbreviation for 'laugh out loud').
'one' becomes 'i' (Roman numeral).
'cheers' becomes 'ta' (both can mean thank you).
'lol' put next to 'i' is 'loli'.
'loli'+'ta'='LOLITA'
(Other definitions for lolita that I've seen before include "novel title" , "Nabokov novel about a nymphet" , "Precocious Nabokov heroine" , "Literary nymphet" , "Seductive young girl" .)