Estimates (7)
I believe the answer is:
guesses
'estimates' is the definition.
(I know this)
This is the entire clue.
(Other definitions for guesses that I've seen before include "Opinions formed with little or no information" , "Hypothesises" , "Forms tentative opinion, thinks likely" , "Conjectures, estimates" , "Conjectures, reckons" .)