One having stiff test perhaps taking look round posh home (3,6)
I believe the answer is:
sea urchin
'one having stiff test perhaps' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'look round posh home' is the wordplay.
'look' becomes 'search' (synonyms).
'round' means one lot of letters goes inside another.
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-U).
'home' becomes 'in' ('he's home' can mean 'he's in').
'search' placed around 'u' is 'seaurch'.
'seaurch'+'in'='SEA-URCHIN'
'taking' is the link.
Can you help me to learn more?
(Other definitions for sea urchin that I've seen before include "spineless creature" , "Marine life form" , "Marine invertebrate with spikes" , "marine echinoderm" , "Shelled marine creature" .)