Acquit Charlie, a tragic figure (5)
I believe the answer is:
clear
'acquit' is the definition.
(I know that acquit can be written as clear)
'charlie a tragic figure' is the wordplay.
'charlie' becomes 'C' (phonetic alphabet).
'a tragic figure' becomes 'lear' (from Shakespeare's King Lear).
'c'+'lear'='CLEAR'
(Other definitions for clear that I've seen before include "Plainly" , "Understandable" , "Patent" , "Lucid, obvious" , "Plain; unblock" .)