Slack tie adult loosened (8)
I believe the answer is:
latitude
'slack' is the definition.
(both can mean leniency or leeway)
'tie adult loosened' is the wordplay.
'loosened' indicates an anagram.
'tie'+'adult'='tieadult'
'tieadult' anagrammed gives 'LATITUDE'.
(Other definitions for latitude that I've seen before include "comes by degrees?" , "Angle from the equator" , "Imaginary line around the earth parallel to the equator" , "seen the world over" , "Distance from pole" .)