Point in the orbit of the moon that's furthest from the earth (6)
I believe the answer is:
apogee
'point in the orbit of the moon that's furthest from the earth' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for apogee that I've seen before include "Highest point (of orbit)" , "Apex, peak" , "'Apex, climax (6)'" , "Culmination, climax" , "Point in planet's orbit when furthest from earth" .)