A name is confused, memory being lost (7)
I believe the answer is:
amnesia
'memory being lost' is the definition.
(amnesia is memory loss)
'a name is confused' is the wordplay.
'confused' indicates anagramming the letters.
'name'+'is'='nameis'
'nameis' anagrammed gives 'mnesia'.
'a'+'mnesia'='AMNESIA'
(Other definitions for amnesia that I've seen before include "Inability to remember" , "Failure to recall" , "Defect in memory" , "Pathological forgetfulness" , "Clinical loss of memory" .)