Adam perhaps is in on the plot (8)
I believe the answer is:
gardener
'adam' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'perhaps is in on the plot' is the wordplay.
I cannot really see how this works, but
'plot' could be 'garden' (garden is a kind of plot) and 'garden' is found in the answer.
The remaining letters 'er' 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 gardener that I've seen before include "Horticultural worker" , "One may get food" , "someone in bed" , "Garnered by worker on cultivated ground" , "One growing plants" .)