Spare room? Not exactly (5)
I believe the answer is:
space
'spare room?' is the definition.
'space' can be an answer for 'room?' (room is a kind of space). I'm not certain of the 'spare' bit.
'not exactly' is the wordplay.
I cannot quite see how this works, but
'not exactly' could be 'c' (short for 'circa') and 'c' is present in the answer.
The remaining letters 'spae' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for space that I've seen before include "sci-fi theme" , "Free area" , "Blank" , "Empty area, may be outer" , "Room for capes" .)