Say you've done the wrong thing (7)
I believe the answer is:
confess
'say' is the definition.
The answer and definition can be both to do with communicating as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for confess that I've seen before include "Plead guilty (in order to receive absolution?)" , "Admit (to crime)" , "Admit (to wrongdoing)" , "Tell a priest one's sins" , "Concede" .)