Hurried back with the unknown plant (7)
I believe the answer is:
narthex
'plant' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'hurried back with the unknown' is the wordplay.
'hurried' becomes 'ran' (running is a kind of hurrying).
'back' shows that the letters should be reversed in order.
'with' is a charade indicator (letters next to each other).
'unknown' becomes 'x' (algebra).
'ran' in reverse letter order is 'nar'.
'nar'+'the'+'x'='NARTHEX'
Can you help me to learn more?
(Another definition for narthex that I've seen is " church portico".)