Person involved in public relations is no amateur (3)
I believe the answer is:
pro
'no amateur' is the definition.
(I've seen this in another clue)
'person involved in public relations' is the wordplay.
I cannot quite see how this works, but
'public relations' could be 'pr' (abbreviation) and 'pr' is present in the answer.
A single letter 'o' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'is' acts as a link.
Can you help me to learn more?
(Other definitions for pro that I've seen before include "Favouring the professional" , "Skilled" , "hooker" , "Top player" , "Of argument, say, in favour of" .)