Lacking accuracy (7)
(Other definitions for inexact that I've seen before include "Not quite right" , "Nice tax (nag.)" , "Fuzzy - untrue" , "Vague" , "Lax" .)
(Other definitions for imprecise that I've seen before include "Lacking exactness" , "Not very nice" , "not quite right" , "Vague" , "Not exact or clearly stated" .)