Last of Close Encounters reflected high opinion (6)
I believe the answer is:
esteem
'high opinion' is the definition.
(I've seen this in another clue)
'last of close encounters reflected' is the wordplay.
'last of' suggests the final letters.
'encounters' becomes 'meets' ('meet' can be a synonym of 'encounter').
'reflected' says the letters should be written backwards (letters reflected back).
The final letter of 'close' is 'e'.
'meets' written backwards gives 'steem'.
'e'+'steem'='ESTEEM'
(Other definitions for esteem that I've seen before include "gain respect" , "Consider" , "Respect and admiration" , "Think well of" , "'Regard, respect (6)'" .)