Think about returning wine present (6)
I believe the answer is:
wonder
'think about' is the definition.
(to wonder about something is to contemplate it)
'returning wine present' is the wordplay.
'returning' is a reversal indicator.
'wine' becomes 'red' (red wine is an example).
'present' becomes 'now' (both can mean the current period).
'red'+'now'='rednow'
'rednow' reversed gives 'WONDER'.
(Other definitions for wonder that I've seen before include "Marvel or question" , "Scene of Alice's adventures" , "Marvellous person; feel doubt" , "Feel doubt; awe" , "Feel curious" .)