One sitting part of hard examination? (5)
I believe the answer is:
poser
'hard examination?' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'one sitting part' is the wordplay.
I cannot really understand how this works, but
'part' could be 'os' (os is a kind of part) and 'os' is found within the answer.
The remaining letters 'per' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
Can you help me to learn more?
(Other definitions for poser that I've seen before include "insincere?" , "Artist's model" , "one who has airs and graces" , "Tricky clue" , "Particularly baffling problem" .)