This may need a warrant for a period of repose, we hear (6)
I believe the answer is:
arrest
'this may need' is the definition.
The definition and answer can be both states of affairs as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'a warrant for a period of repose we hear' is the wordplay.
I cannot quite see how this works, but
'a' is present in the answer.
'period' could be 'rest' (rest is a kind of period) and 'rest' is found within the answer.
A single letter 'r' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for arrest that I've seen before include "Cause to stop" , "Stop or slow down the progress of" , "Catch" , "Take into custody as police do" , "Apprehend; detain" .)