Appraise organ aloft (3,2)
I believe the answer is:
'appraise' is the definition.
(eye up can mean to appraise or evaluate visually)
'organ aloft' is the wordplay.
'organ' becomes 'eye' (eye is a kind of organ).
'aloft' becomes 'up' (up above).
(Other definitions for eye up that I've seen before include "Look at (someone) as a potential partner" , "Look at (someone) appraisingly" , "Ogle" , "Consider sexual attractiveness of (someone)" , "study" .)