Let slip one had ceased to have anything to do with (7)
I believe the answer is:
dropped
'let slip one had ceased' is the definition.
I can't tell whether this defines the answer.
'have anything to do with' is the wordplay.
I cannot quite see how this works, but
'have' could be 'drop' (dropping is a kind of having) and 'drop' is found in the answer.
The remaining letters 'ped' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'to' is the link.
Can you help me to learn more?
(Other definitions for dropped that I've seen before include "Relinquished" , "Left out of the team" , "Fell; abandoned" , "Let fall" .)