Reckon, suppose (4)
I believe the answer is:
deem
I believe this clue is a double definition.
'reckon' is the first definition.
(I know that deem is a kind of reckon)
'suppose' is the second definition.
(I've seen this in another clue)
(Other definitions for deem that I've seen before include "Adjudge" , "Believe" , "Judge, think, consider" , "Regard, consider" , "Regard in a specific way" .)