Some months, he reckons (6)
I believe the answer is:
summer
'some' is the definition.
Both the answer and definition are adjectives. Maybe you can see a link between them that I don't see?
'months he reckons' is the wordplay.
I cannot quite understand how this works, but
'months' could be 'm' and 'm' is found in the answer.
The remaining letters 'sumer' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for summer that I've seen before include "Mathematician" , "` `Now is the winter of our discontent / Made glorious ... by this sum of York' ' (Richard III)" , "Beam" , "'. . . . . . time an' the livin' is easy' (song)" , "Adder" .)