Beano section: Snooty's back! (5)
I believe the answer is:
party
'beano' is the definition.
(thesaurus)
'section snooty's back' is the wordplay.
'section' becomes 'part' (synonyms).
'back' indicates one should take the final letters (the letter at the back).
The last letter of 'snooty' is 'y'.
'part'+'y'='PARTY'
(Other definitions for party that I've seen before include "push the boat out" , "Social function" , "Festivity" , "eg Labour, Conservative" , "Political organization" .)