It supports one who is lying (8)
I believe the answer is:
bedstead
'lying' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'it supports one who is' is the wordplay.
I cannot quite see how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is located in the answer.
'one' could be 'a' (a thing is one thing) and 'a' is located in the answer.
'is' could be 'be' and 'be' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for bedstead that I've seen before include "Frame upon which a mattress sits" , "Mattress support" , "Framework supporting a sleeper" , "support for the retired" , "Framework supporting springs and mattresses" .)