Bring up small seat (4)
I believe the answer is:
spew
'bring up' is the definition.
(thesaurus)
'small seat' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'seat' becomes 'pew' (pew is a kind of seat).
's'+'pew'='SPEW'
(Other definitions for spew that I've seen before include "issue" , "Forcibly eject" , "Be expelled rapidly in large quantities" , "Spit or stream out" , "Casst out in a stream" .)