Agree to fix story expressing source of alibi (6)
I believe the answer is:
settle
'alibi' 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?
'agree to fix story expressing source of' is the wordplay.
'agree' becomes 'set' (as in to set a date).
'to fix story' becomes 'tl' (I can't explain this - if you can you should give a lot more credence to this answer).
'source of' says to take the initial letters.
The first letter of 'expressing' is 'e'.
'set'+'tl'+'e'='SETTLE'
Can you help me to learn more?
(Other definitions for settle that I've seen before include "Become calm and quiet" , "Arrange; colonise" , "Comes to an arrangement with the bench?" , "small market town" , "Resolve; come to rest" .)