Reckon inn's patrons must have time out (5)
I believe the answer is:
guess
'reckon' is the definition.
(I know that reckon can be written as guess)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for guess that I've seen before include "Surmise" , "Estimate on the basis of little information" , "Fancy" , "Divine - estimate" , "Hypothesis" .)