Endlessly observe Magritte being calm? (6)
I believe the answer is:
serene
'being calm?' is the definition.
('serene' can be a synonym of 'calm')
'endlessly observe magritte' is the wordplay.
'endlessly' means to remove the last letter.
'observe' becomes 'see' (I've seen this in other clues).
'magritte' becomes 'rene' (artist Rene Magritte).
'see' with its last letter taken off is 'se'.
'se'+'rene'='SERENE'
(Other definitions for serene that I've seen before include "Peaceful and contented" , "Fair" , "still" , "Calm and unruffled, like a princely title." , "without any trouble" .)