Say about half your height (7)
I believe the answer is:
stature
'height' is the definition.
('stature' can be a synonym of 'height')
'say about half your' is the wordplay.
'say' becomes 'state' ('state' can be a synonym of 'say'**).
'about' indicates putting letters inside.
'half' means to take half the letters.
'your' cut in half is 'ur'.
'state' enclosing 'ur' is 'STATURE'.
(Other definitions for stature that I've seen before include "Height - prestige" , "Height, calibre" , "moral greatness" , "Importance, reputation" , "level of achievement" .)