Get behind fun-loving trio and try to forget (7)
I believe the answer is:
unlearn
'try to forget' is the definition.
(synonyms)
'get behind fun-loving trio and' is the wordplay.
I cannot really see how this works, but
'get' could be 'learn' (I've seen this before) and 'learn' is located in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is present in the answer.
A single letter 'u' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for unlearn that I've seen before include "Cease to hold (previous teaching)" , "Deliberately forget" , "Try to forget something" .)