A social climber sent back one plant such as this (6)
I believe the answer is:
bonsai
'plant such as this' is the definition.
The definition suggests a singular noun which matches the answer.
'a social climber sent back one' is the wordplay.
'social climber' becomes 'snob' (I've seen this before).
'sent back' is a reversal indicator.
'one' becomes 'i' (Roman numeral).
'a'+'snob'='asnob'
'asnob' backwards is 'bonsa'.
'bonsa'+'i'='BONSAI'
Can you help me to learn more?
(Other definitions for bonsai that I've seen before include "Dwarfed ornamental tree or shrub" , "The art of growing ornamental dwarfed plants" , "stunted growth" , "Tiny Japanese tree" , "Dwarf tree found in Bosnia" .)